org.apache.hadoop.yarn.conf.YarnConfiguration.java Source code

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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package org.apache.hadoop.yarn.conf;

import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import org.apache.hadoop.HadoopIllegalArgumentException;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
import org.apache.hadoop.classification.InterfaceStability.Unstable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.CommonConfigurationKeys;
import org.apache.hadoop.ha.ActiveStandbyElector;
import org.apache.hadoop.http.HttpConfig;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.util.BasicDiskValidator;
import org.apache.hadoop.util.StringUtils;
import org.apache.hadoop.yarn.api.ApplicationConstants;

@Public
@Evolving
public class YarnConfiguration extends Configuration {

    @Private
    public static final String DR_CONFIGURATION_FILE = "dynamic-resources.xml";

    @Private
    public static final String CS_CONFIGURATION_FILE = "capacity-scheduler.xml";

    @Private
    public static final String HADOOP_POLICY_CONFIGURATION_FILE = "hadoop-policy.xml";

    @Private
    public static final String YARN_SITE_CONFIGURATION_FILE = "yarn-site.xml";

    private static final String YARN_DEFAULT_CONFIGURATION_FILE = "yarn-default.xml";

    @Private
    public static final String CORE_SITE_CONFIGURATION_FILE = "core-site.xml";

    @Private
    public static final String RESOURCE_TYPES_CONFIGURATION_FILE = "resource-types.xml";

    @Private
    public static final String NODE_RESOURCES_CONFIGURATION_FILE = "node-resources.xml";

    @Private
    public static final List<String> RM_CONFIGURATION_FILES = Collections.unmodifiableList(
            Arrays.asList(RESOURCE_TYPES_CONFIGURATION_FILE, DR_CONFIGURATION_FILE, CS_CONFIGURATION_FILE,
                    HADOOP_POLICY_CONFIGURATION_FILE, YARN_SITE_CONFIGURATION_FILE, CORE_SITE_CONFIGURATION_FILE));

    @Private
    public static final List<String> NM_CONFIGURATION_FILES = Collections.unmodifiableList(
            Arrays.asList(NODE_RESOURCES_CONFIGURATION_FILE, DR_CONFIGURATION_FILE, CS_CONFIGURATION_FILE,
                    HADOOP_POLICY_CONFIGURATION_FILE, YARN_SITE_CONFIGURATION_FILE, CORE_SITE_CONFIGURATION_FILE));

    @Evolving
    public static final int APPLICATION_MAX_TAGS = 10;

    @Evolving
    public static final int APPLICATION_MAX_TAG_LENGTH = 100;

    static {
        addDeprecatedKeys();
        Configuration.addDefaultResource(YARN_DEFAULT_CONFIGURATION_FILE);
        Configuration.addDefaultResource(YARN_SITE_CONFIGURATION_FILE);
    }

    private static void addDeprecatedKeys() {
        Configuration.addDeprecations(new DeprecationDelta[] {
                new DeprecationDelta("yarn.client.max-nodemanagers-proxies", NM_CLIENT_MAX_NM_PROXIES) });
        Configuration.addDeprecations(new DeprecationDelta[] {
                new DeprecationDelta(RM_SYSTEM_METRICS_PUBLISHER_ENABLED, SYSTEM_METRICS_PUBLISHER_ENABLED),
                new DeprecationDelta(RM_ZK_ACL, CommonConfigurationKeys.ZK_ACL),
                new DeprecationDelta(RM_ZK_AUTH, CommonConfigurationKeys.ZK_AUTH),
                new DeprecationDelta(RM_ZK_ADDRESS, CommonConfigurationKeys.ZK_ADDRESS),
                new DeprecationDelta(RM_ZK_NUM_RETRIES, CommonConfigurationKeys.ZK_NUM_RETRIES),
                new DeprecationDelta(RM_ZK_TIMEOUT_MS, CommonConfigurationKeys.ZK_TIMEOUT_MS),
                new DeprecationDelta(RM_ZK_RETRY_INTERVAL_MS, CommonConfigurationKeys.ZK_RETRY_INTERVAL_MS), });
        Configuration.addDeprecations(new DeprecationDelta[] {
                new DeprecationDelta("yarn.resourcemanager.display.per-user-apps", FILTER_ENTITY_LIST_BY_USER) });
    }

    //Configurations

    public static final String YARN_PREFIX = "yarn.";

    /////////////////////////////
    // Resource types configs
    ////////////////////////////

    public static final String RESOURCE_TYPES = YarnConfiguration.YARN_PREFIX + "resource-types";

    public static final String NM_RESOURCES_PREFIX = YarnConfiguration.NM_PREFIX + "resource-type.";

    /** Delay before deleting resource to ease debugging of NM issues */
    public static final String DEBUG_NM_DELETE_DELAY_SEC = YarnConfiguration.NM_PREFIX + "delete.debug-delay-sec";

    public static final String NM_LOG_CONTAINER_DEBUG_INFO = YarnConfiguration.NM_PREFIX
            + "log-container-debug-info.enabled";

    public static final boolean DEFAULT_NM_LOG_CONTAINER_DEBUG_INFO = true;

    ////////////////////////////////
    // IPC Configs
    ////////////////////////////////
    public static final String IPC_PREFIX = YARN_PREFIX + "ipc.";

    /** Factory to create client IPC classes.*/
    public static final String IPC_CLIENT_FACTORY_CLASS = IPC_PREFIX + "client.factory.class";
    public static final String DEFAULT_IPC_CLIENT_FACTORY_CLASS = "org.apache.hadoop.yarn.factories.impl.pb.RpcClientFactoryPBImpl";

    /** Factory to create server IPC classes.*/
    public static final String IPC_SERVER_FACTORY_CLASS = IPC_PREFIX + "server.factory.class";
    public static final String DEFAULT_IPC_SERVER_FACTORY_CLASS = "org.apache.hadoop.yarn.factories.impl.pb.RpcServerFactoryPBImpl";

    /** Factory to create serializable records.*/
    public static final String IPC_RECORD_FACTORY_CLASS = IPC_PREFIX + "record.factory.class";
    public static final String DEFAULT_IPC_RECORD_FACTORY_CLASS = "org.apache.hadoop.yarn.factories.impl.pb.RecordFactoryPBImpl";

    /** RPC class implementation*/
    public static final String IPC_RPC_IMPL = IPC_PREFIX + "rpc.class";
    public static final String DEFAULT_IPC_RPC_IMPL = "org.apache.hadoop.yarn.ipc.HadoopYarnProtoRPC";

    ////////////////////////////////
    // Resource Manager Configs
    ////////////////////////////////
    public static final String RM_PREFIX = "yarn.resourcemanager.";

    public static final String RM_CLUSTER_ID = RM_PREFIX + "cluster-id";
    public static final String DEFAULT_RM_CLUSTER_ID = "yarn_cluster";

    public static final String RM_HOSTNAME = RM_PREFIX + "hostname";

    public static final String RM_EPOCH = RM_PREFIX + "epoch";
    public static final long DEFAULT_RM_EPOCH = 0L;

    /** The epoch range before wrap around. 0 disables wrap around*/
    public static final String RM_EPOCH_RANGE = RM_EPOCH + ".range";
    public static final long DEFAULT_RM_EPOCH_RANGE = 0;

    /** The address of the applications manager interface in the RM.*/
    public static final String RM_ADDRESS = RM_PREFIX + "address";
    public static final int DEFAULT_RM_PORT = 8032;
    public static final String DEFAULT_RM_ADDRESS = "0.0.0.0:" + DEFAULT_RM_PORT;

    public static final String RM_APPLICATION_MASTER_SERVICE_PROCESSORS = RM_PREFIX
            + "application-master-service.processors";

    public static final String RM_AUTO_UPDATE_CONTAINERS = RM_PREFIX + "auto-update.containers";
    public static final boolean DEFAULT_RM_AUTO_UPDATE_CONTAINERS = false;

    /** The actual bind address for the RM.*/
    public static final String RM_BIND_HOST = RM_PREFIX + "bind-host";

    /** The number of threads used to handle applications manager requests.*/
    public static final String RM_CLIENT_THREAD_COUNT = RM_PREFIX + "client.thread-count";
    public static final int DEFAULT_RM_CLIENT_THREAD_COUNT = 50;

    /** Number of threads used to launch/cleanup AM.*/
    public static final String RM_AMLAUNCHER_THREAD_COUNT = RM_PREFIX + "amlauncher.thread-count";
    public static final int DEFAULT_RM_AMLAUNCHER_THREAD_COUNT = 50;

    /** Retry times to connect with NM.*/
    public static final String RM_NODEMANAGER_CONNECT_RETRIES = RM_PREFIX + "nodemanager-connect-retries";
    public static final int DEFAULT_RM_NODEMANAGER_CONNECT_RETRIES = 10;

    /** The Kerberos principal for the resource manager.*/
    public static final String RM_PRINCIPAL = RM_PREFIX + "principal";

    /** The address of the scheduler interface.*/
    public static final String RM_SCHEDULER_ADDRESS = RM_PREFIX + "scheduler.address";
    public static final int DEFAULT_RM_SCHEDULER_PORT = 8030;
    public static final String DEFAULT_RM_SCHEDULER_ADDRESS = "0.0.0.0:" + DEFAULT_RM_SCHEDULER_PORT;

    /** Minimum request grant-able by the RM scheduler. */
    public static final String RM_SCHEDULER_MINIMUM_ALLOCATION_MB = YARN_PREFIX + "scheduler.minimum-allocation-mb";
    public static final int DEFAULT_RM_SCHEDULER_MINIMUM_ALLOCATION_MB = 1024;
    public static final String RM_SCHEDULER_MINIMUM_ALLOCATION_VCORES = YARN_PREFIX
            + "scheduler.minimum-allocation-vcores";
    public static final int DEFAULT_RM_SCHEDULER_MINIMUM_ALLOCATION_VCORES = 1;

    /** Maximum request grant-able by the RM scheduler. */
    public static final String RM_SCHEDULER_MAXIMUM_ALLOCATION_MB = YARN_PREFIX + "scheduler.maximum-allocation-mb";
    public static final int DEFAULT_RM_SCHEDULER_MAXIMUM_ALLOCATION_MB = 8192;
    public static final String RM_SCHEDULER_MAXIMUM_ALLOCATION_VCORES = YARN_PREFIX
            + "scheduler.maximum-allocation-vcores";
    public static final int DEFAULT_RM_SCHEDULER_MAXIMUM_ALLOCATION_VCORES = 4;

    /** Number of threads to handle scheduler interface.*/
    public static final String RM_SCHEDULER_CLIENT_THREAD_COUNT = RM_PREFIX + "scheduler.client.thread-count";
    public static final int DEFAULT_RM_SCHEDULER_CLIENT_THREAD_COUNT = 50;

    /** If the port should be included or not in the node name. The node name
     * is used by the scheduler for resource requests allocation location 
     * matching. Typically this is just the hostname, using the port is needed
     * when using minicluster and specific NM are required.*/
    public static final String RM_SCHEDULER_INCLUDE_PORT_IN_NODE_NAME = YARN_PREFIX
            + "scheduler.include-port-in-node-name";
    public static final boolean DEFAULT_RM_SCHEDULER_USE_PORT_FOR_NODE_NAME = false;

    /** Configured scheduler queue placement rules. */
    public static final String QUEUE_PLACEMENT_RULES = YARN_PREFIX + "scheduler.queue-placement-rules";
    /** UserGroupMappingPlacementRule configuration string. */
    public static final String USER_GROUP_PLACEMENT_RULE = "user-group";

    public static final String APP_NAME_PLACEMENT_RULE = "app-name";

    /** Enable Resource Manager webapp ui actions */
    public static final String RM_WEBAPP_UI_ACTIONS_ENABLED = RM_PREFIX + "webapp.ui-actions.enabled";
    public static final boolean DEFAULT_RM_WEBAPP_UI_ACTIONS_ENABLED = true;

    /** Whether the RM should enable Reservation System */
    public static final String RM_RESERVATION_SYSTEM_ENABLE = RM_PREFIX + "reservation-system.enable";
    public static final boolean DEFAULT_RM_RESERVATION_SYSTEM_ENABLE = false;

    /** The class to use as the Reservation System. */
    public static final String RM_RESERVATION_SYSTEM_CLASS = RM_PREFIX + "reservation-system.class";

    /** The PlanFollower for the Reservation System. */
    public static final String RM_RESERVATION_SYSTEM_PLAN_FOLLOWER = RM_PREFIX + "reservation-system.plan.follower";

    /** The step size of the Reservation System. */
    public static final String RM_RESERVATION_SYSTEM_PLAN_FOLLOWER_TIME_STEP = RM_PREFIX
            + "reservation-system.planfollower.time-step";
    public static final long DEFAULT_RM_RESERVATION_SYSTEM_PLAN_FOLLOWER_TIME_STEP = 1000L;

    /** The maximum periodicity for the Reservation System. */
    public static final String RM_RESERVATION_SYSTEM_MAX_PERIODICITY = RM_PREFIX
            + "reservation-system.max-periodicity";
    public static final long DEFAULT_RM_RESERVATION_SYSTEM_MAX_PERIODICITY = 86400000L;

    /**
     * Enable periodic monitor threads.
     * @see #RM_SCHEDULER_MONITOR_POLICIES
     */
    public static final String RM_SCHEDULER_ENABLE_MONITORS = RM_PREFIX + "scheduler.monitor.enable";
    public static final boolean DEFAULT_RM_SCHEDULER_ENABLE_MONITORS = false;

    /** List of SchedulingEditPolicy classes affecting the scheduler. */
    public static final String RM_SCHEDULER_MONITOR_POLICIES = RM_PREFIX + "scheduler.monitor.policies";

    /** The address of the RM web application.*/
    public static final String RM_WEBAPP_ADDRESS = RM_PREFIX + "webapp.address";

    public static final int DEFAULT_RM_WEBAPP_PORT = 8088;
    public static final String DEFAULT_RM_WEBAPP_ADDRESS = "0.0.0.0:" + DEFAULT_RM_WEBAPP_PORT;

    /** The https address of the RM web application.*/
    public static final String RM_WEBAPP_HTTPS_ADDRESS = RM_PREFIX + "webapp.https.address";
    public static final boolean YARN_SSL_CLIENT_HTTPS_NEED_AUTH_DEFAULT = false;
    public static final String YARN_SSL_SERVER_RESOURCE_DEFAULT = "ssl-server.xml";

    public static final int DEFAULT_RM_WEBAPP_HTTPS_PORT = 8090;
    public static final String DEFAULT_RM_WEBAPP_HTTPS_ADDRESS = "0.0.0.0:" + DEFAULT_RM_WEBAPP_HTTPS_PORT;

    /**
     * Enable YARN WebApp V2.
     */
    public static final String YARN_WEBAPP_UI2_ENABLE = "yarn." + "webapp.ui2.enable";
    public static final boolean DEFAULT_YARN_WEBAPP_UI2_ENABLE = false;

    public static final String YARN_WEBAPP_UI2_WARFILE_PATH = "yarn." + "webapp.ui2.war-file-path";
    public static final String YARN_API_SERVICES_ENABLE = "yarn." + "webapp.api-service.enable";

    @Private
    public static final String DEFAULT_YARN_API_SYSTEM_SERVICES_CLASS = "org.apache.hadoop.yarn.service.client.SystemServiceManagerImpl";

    public static final String RM_RESOURCE_TRACKER_ADDRESS = RM_PREFIX + "resource-tracker.address";
    public static final int DEFAULT_RM_RESOURCE_TRACKER_PORT = 8031;
    public static final String DEFAULT_RM_RESOURCE_TRACKER_ADDRESS = "0.0.0.0:" + DEFAULT_RM_RESOURCE_TRACKER_PORT;

    /** The expiry interval for application master reporting.*/
    public static final String RM_AM_EXPIRY_INTERVAL_MS = YARN_PREFIX + "am.liveness-monitor.expiry-interval-ms";
    public static final int DEFAULT_RM_AM_EXPIRY_INTERVAL_MS = 600000;

    /** How long to wait until a node manager is considered dead.*/
    public static final String RM_NM_EXPIRY_INTERVAL_MS = YARN_PREFIX + "nm.liveness-monitor.expiry-interval-ms";
    public static final int DEFAULT_RM_NM_EXPIRY_INTERVAL_MS = 600000;

    /** Are acls enabled.*/
    public static final String YARN_ACL_ENABLE = YARN_PREFIX + "acl.enable";
    public static final boolean DEFAULT_YARN_ACL_ENABLE = false;

    /** Are reservation acls enabled.*/
    public static final String YARN_RESERVATION_ACL_ENABLE = YARN_PREFIX + "acl.reservation-enable";
    public static final boolean DEFAULT_YARN_RESERVATION_ACL_ENABLE = false;

    public static boolean isAclEnabled(Configuration conf) {
        return conf.getBoolean(YARN_ACL_ENABLE, DEFAULT_YARN_ACL_ENABLE);
    }

    /** ACL of who can be admin of YARN cluster.*/
    public static final String YARN_ADMIN_ACL = YARN_PREFIX + "admin.acl";
    public static final String DEFAULT_YARN_ADMIN_ACL = "*";

    /** ACL used in case none is found. Allows nothing. */
    public static final String DEFAULT_YARN_APP_ACL = " ";

    /** Setting that controls whether opportunistic container allocation
     *  is enabled or not. */
    @Unstable
    public static final String OPPORTUNISTIC_CONTAINER_ALLOCATION_ENABLED = RM_PREFIX
            + "opportunistic-container-allocation.enabled";
    public static final boolean DEFAULT_OPPORTUNISTIC_CONTAINER_ALLOCATION_ENABLED = false;

    /** Number of nodes to be used by the Opportunistic Container allocator for
     * dispatching containers during container allocation. */
    @Unstable
    public static final String OPP_CONTAINER_ALLOCATION_NODES_NUMBER_USED = RM_PREFIX
            + "opportunistic-container-allocation.nodes-used";
    public static final int DEFAULT_OPP_CONTAINER_ALLOCATION_NODES_NUMBER_USED = 10;

    /** Frequency for computing least loaded NMs. */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_SORTING_NODES_INTERVAL_MS = RM_PREFIX
            + "nm-container-queuing.sorting-nodes-interval-ms";
    public static final long DEFAULT_NM_CONTAINER_QUEUING_SORTING_NODES_INTERVAL_MS = 1000;

    /** Comparator for determining node load for scheduling of opportunistic
     * containers. */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_LOAD_COMPARATOR = RM_PREFIX
            + "nm-container-queuing.load-comparator";
    public static final String DEFAULT_NM_CONTAINER_QUEUING_LOAD_COMPARATOR = "QUEUE_LENGTH";

    /** Value of standard deviation used for calculation of queue limit
     * thresholds. */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_LIMIT_STDEV = RM_PREFIX
            + "nm-container-queuing.queue-limit-stdev";
    public static final float DEFAULT_NM_CONTAINER_QUEUING_LIMIT_STDEV = 1.0f;

    /** Min length of container queue at NodeManager. This is a cluster-wide
     * configuration that acts as the lower-bound of optimal queue length
     * calculated by the NodeQueueLoadMonitor */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_MIN_QUEUE_LENGTH = RM_PREFIX
            + "nm-container-queuing.min-queue-length";
    public static final int DEFAULT_NM_CONTAINER_QUEUING_MIN_QUEUE_LENGTH = 5;

    /** Max length of container queue at NodeManager. This is a cluster-wide
     * configuration that acts as the upper-bound of optimal queue length
     * calculated by the NodeQueueLoadMonitor */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_MAX_QUEUE_LENGTH = RM_PREFIX
            + "nm-container-queuing.max-queue-length";
    public static final int DEFAULT_NM_CONTAINER_QUEUING_MAX_QUEUE_LENGTH = 15;

    /** Min queue wait time for a container at a NodeManager. */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_MIN_QUEUE_WAIT_TIME_MS = RM_PREFIX
            + "nm-container-queuing.min-queue-wait-time-ms";
    public static final int DEFAULT_NM_CONTAINER_QUEUING_MIN_QUEUE_WAIT_TIME_MS = 10;

    /** Max queue wait time for a container queue at a NodeManager. */
    @Unstable
    public static final String NM_CONTAINER_QUEUING_MAX_QUEUE_WAIT_TIME_MS = RM_PREFIX
            + "nm-container-queuing.max-queue-wait-time-ms";
    public static final int DEFAULT_NM_CONTAINER_QUEUING_MAX_QUEUE_WAIT_TIME_MS = 100;

    /**
     * Enable/disable intermediate-data encryption at YARN level. For now, this
     * only is used by the FileSystemRMStateStore to setup right file-system
     * security attributes.
     */
    @Private
    public static final String YARN_INTERMEDIATE_DATA_ENCRYPTION = YARN_PREFIX
            + "intermediate-data-encryption.enable";

    @Private
    public static final boolean DEFAULT_YARN_INTERMEDIATE_DATA_ENCRYPTION = false;

    /** The address of the RM admin interface.*/
    public static final String RM_ADMIN_ADDRESS = RM_PREFIX + "admin.address";
    public static final int DEFAULT_RM_ADMIN_PORT = 8033;
    public static final String DEFAULT_RM_ADMIN_ADDRESS = "0.0.0.0:" + DEFAULT_RM_ADMIN_PORT;

    /**Number of threads used to handle RM admin interface.*/
    public static final String RM_ADMIN_CLIENT_THREAD_COUNT = RM_PREFIX + "admin.client.thread-count";
    public static final int DEFAULT_RM_ADMIN_CLIENT_THREAD_COUNT = 1;

    /**
     * The maximum number of application attempts.
     * It's a global setting for all application masters.
     */
    public static final String RM_AM_MAX_ATTEMPTS = RM_PREFIX + "am.max-attempts";
    public static final int DEFAULT_RM_AM_MAX_ATTEMPTS = 2;

    /** The keytab for the resource manager.*/
    public static final String RM_KEYTAB = RM_PREFIX + "keytab";

    /**The kerberos principal to be used for spnego filter for RM.*/
    public static final String RM_WEBAPP_SPNEGO_USER_NAME_KEY = RM_PREFIX + "webapp.spnego-principal";

    /**The kerberos keytab to be used for spnego filter for RM.*/
    public static final String RM_WEBAPP_SPNEGO_KEYTAB_FILE_KEY = RM_PREFIX + "webapp.spnego-keytab-file";

    /**
     * Flag to enable override of the default kerberos authentication filter with
     * the RM authentication filter to allow authentication using delegation
     * tokens(fallback to kerberos if the tokens are missing). Only applicable
     * when the http authentication type is kerberos.
     */
    public static final String RM_WEBAPP_DELEGATION_TOKEN_AUTH_FILTER = RM_PREFIX
            + "webapp.delegation-token-auth-filter.enabled";
    public static final boolean DEFAULT_RM_WEBAPP_DELEGATION_TOKEN_AUTH_FILTER = true;

    /** Enable cross origin (CORS) support. **/
    public static final String RM_WEBAPP_ENABLE_CORS_FILTER = RM_PREFIX + "webapp.cross-origin.enabled";
    public static final boolean DEFAULT_RM_WEBAPP_ENABLE_CORS_FILTER = false;

    /** How long to wait until a container is considered dead.*/
    public static final String RM_CONTAINER_ALLOC_EXPIRY_INTERVAL_MS = RM_PREFIX
            + "rm.container-allocation.expiry-interval-ms";
    public static final int DEFAULT_RM_CONTAINER_ALLOC_EXPIRY_INTERVAL_MS = 600000;

    /** Path to file with nodes to include.*/
    public static final String RM_NODES_INCLUDE_FILE_PATH = RM_PREFIX + "nodes.include-path";
    public static final String DEFAULT_RM_NODES_INCLUDE_FILE_PATH = "";

    /** Path to file with nodes to exclude.*/
    public static final String RM_NODES_EXCLUDE_FILE_PATH = RM_PREFIX + "nodes.exclude-path";
    public static final String DEFAULT_RM_NODES_EXCLUDE_FILE_PATH = "";

    /** Number of threads to handle resource tracker calls.*/
    public static final String RM_RESOURCE_TRACKER_CLIENT_THREAD_COUNT = RM_PREFIX
            + "resource-tracker.client.thread-count";
    public static final int DEFAULT_RM_RESOURCE_TRACKER_CLIENT_THREAD_COUNT = 50;

    /** The class to use as the resource scheduler.*/
    public static final String RM_SCHEDULER = RM_PREFIX + "scheduler.class";

    /**
     * Specify which handler will be used to process PlacementConstraints.
     * For details on PlacementConstraints, please refer to
     * {@link org.apache.hadoop.yarn.api.resource.PlacementConstraint}
     */
    @Private
    public static final String RM_PLACEMENT_CONSTRAINTS_HANDLER = RM_PREFIX + "placement-constraints.handler";

    /**
     * This handler rejects all allocate calls made by an application, if they
     * contain a {@link org.apache.hadoop.yarn.api.records.SchedulingRequest}.
     */
    @Private
    public static final String DISABLED_RM_PLACEMENT_CONSTRAINTS_HANDLER = "disabled";

    /**
     * Using this handler, the placement of containers with constraints is
     * determined as a pre-processing step before the capacity or the fair
     * scheduler is called. Once the placement is decided, the capacity/fair
     * scheduler is invoked to perform the actual allocation. The advantage of
     * this approach is that it supports all constraint types (affinity,
     * anti-affinity, cardinality). Moreover, it considers multiple containers at
     * a time, which allows to satisfy more constraints than a container-at-a-time
     * approach can achieve. As it sits outside the main scheduler, it can be used
     * by both the capacity and fair schedulers. Note that at the moment it does
     * not account for task priorities within an application, given that such
     * priorities might be conflicting with the placement constraints.
     */
    @Private
    public static final String PROCESSOR_RM_PLACEMENT_CONSTRAINTS_HANDLER = "placement-processor";

    /**
     * Using this handler, containers with constraints will be placed by the main
     * scheduler. If the configured RM scheduler
     * <pre>yarn.resourcemanager.scheduler.class</pre>
     * cannot handle placement constraints, the corresponding SchedulingRequests
     * will be rejected. As of now, only the capacity scheduler supports
     * SchedulingRequests. In particular, it currently supports anti-affinity
     * constraints (no affinity or cardinality) and places one container at a
     * time. The advantage of this handler compared to the placement-processor is
     * that it follows the same ordering rules for queues (sorted by utilization,
     * priority) and apps (sorted by FIFO/fairness/priority) as the ones followed
     * by the main scheduler.
     */
    @Private
    public static final String SCHEDULER_RM_PLACEMENT_CONSTRAINTS_HANDLER = "scheduler";

    /** Placement Algorithm. */
    public static final String RM_PLACEMENT_CONSTRAINTS_ALGORITHM_CLASS = RM_PREFIX
            + "placement-constraints.algorithm.class";

    /** Used for BasicPlacementAlgorithm - default SERIAL. **/
    public static final String RM_PLACEMENT_CONSTRAINTS_ALGORITHM_ITERATOR = RM_PREFIX
            + "placement-constraints.algorithm.iterator";

    public static final String RM_PLACEMENT_CONSTRAINTS_RETRY_ATTEMPTS = RM_PREFIX
            + "placement-constraints.retry-attempts";

    public static final int DEFAULT_RM_PLACEMENT_CONSTRAINTS_RETRY_ATTEMPTS = 3;

    public static final String RM_PLACEMENT_CONSTRAINTS_ALGORITHM_POOL_SIZE = RM_PREFIX
            + "placement-constraints.algorithm.pool-size";

    public static final int DEFAULT_RM_PLACEMENT_CONSTRAINTS_ALGORITHM_POOL_SIZE = 1;

    public static final String RM_PLACEMENT_CONSTRAINTS_SCHEDULER_POOL_SIZE = RM_PREFIX
            + "placement-constraints.scheduler.pool-size";

    public static final int DEFAULT_RM_PLACEMENT_CONSTRAINTS_SCHEDULER_POOL_SIZE = 1;

    public static final String DEFAULT_RM_SCHEDULER = "org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler";

    /** RM set next Heartbeat interval for NM */
    public static final String RM_NM_HEARTBEAT_INTERVAL_MS = RM_PREFIX + "nodemanagers.heartbeat-interval-ms";
    public static final long DEFAULT_RM_NM_HEARTBEAT_INTERVAL_MS = 1000;

    /** Number of worker threads that write the history data. */
    public static final String RM_HISTORY_WRITER_MULTI_THREADED_DISPATCHER_POOL_SIZE = RM_PREFIX
            + "history-writer.multi-threaded-dispatcher.pool-size";
    public static final int DEFAULT_RM_HISTORY_WRITER_MULTI_THREADED_DISPATCHER_POOL_SIZE = 10;

    /**
     *  The setting that controls whether yarn system metrics is published on the
     *  timeline server or not by RM. This configuration setting is for ATS V1.
     *  This is now deprecated in favor of SYSTEM_METRICS_PUBLISHER_ENABLED.
     */
    public static final String RM_SYSTEM_METRICS_PUBLISHER_ENABLED = RM_PREFIX + "system-metrics-publisher.enabled";
    public static final boolean DEFAULT_RM_SYSTEM_METRICS_PUBLISHER_ENABLED = false;

    /**
     *  The setting that controls whether yarn system metrics is published on the
     *  timeline server or not by RM and NM. This configuration setting is for
     *  ATS v2.
     */
    public static final String SYSTEM_METRICS_PUBLISHER_ENABLED = YARN_PREFIX + "system-metrics-publisher.enabled";
    public static final boolean DEFAULT_SYSTEM_METRICS_PUBLISHER_ENABLED = false;

    /**
     * The setting that controls whether yarn container events are published to
     * the timeline service or not by RM. This configuration setting is for ATS
     * V2
     */
    public static final String RM_PUBLISH_CONTAINER_EVENTS_ENABLED = YARN_PREFIX
            + "rm.system-metrics-publisher.emit-container-events";
    public static final boolean DEFAULT_RM_PUBLISH_CONTAINER_EVENTS_ENABLED = false;

    public static final String RM_SYSTEM_METRICS_PUBLISHER_DISPATCHER_POOL_SIZE = RM_PREFIX
            + "system-metrics-publisher.dispatcher.pool-size";
    public static final int DEFAULT_RM_SYSTEM_METRICS_PUBLISHER_DISPATCHER_POOL_SIZE = 10;

    //RM delegation token related keys
    public static final String RM_DELEGATION_KEY_UPDATE_INTERVAL_KEY = RM_PREFIX + "delegation.key.update-interval";
    public static final long RM_DELEGATION_KEY_UPDATE_INTERVAL_DEFAULT = 24 * 60 * 60 * 1000; // 1 day
    public static final String RM_DELEGATION_TOKEN_RENEW_INTERVAL_KEY = RM_PREFIX
            + "delegation.token.renew-interval";
    public static final long RM_DELEGATION_TOKEN_RENEW_INTERVAL_DEFAULT = 24 * 60 * 60 * 1000; // 1 day
    public static final String RM_DELEGATION_TOKEN_MAX_LIFETIME_KEY = RM_PREFIX + "delegation.token.max-lifetime";
    public static final long RM_DELEGATION_TOKEN_MAX_LIFETIME_DEFAULT = 7 * 24 * 60 * 60 * 1000; // 7 days

    public static final String RM_DELEGATION_TOKEN_MAX_CONF_SIZE = RM_PREFIX
            + "delegation-token.max-conf-size-bytes";
    public static final int DEFAULT_RM_DELEGATION_TOKEN_MAX_CONF_SIZE_BYTES = 12800;

    public static final String RECOVERY_ENABLED = RM_PREFIX + "recovery.enabled";
    public static final boolean DEFAULT_RM_RECOVERY_ENABLED = false;

    public static final String YARN_FAIL_FAST = YARN_PREFIX + "fail-fast";
    public static final boolean DEFAULT_YARN_FAIL_FAST = false;

    public static final String RM_FAIL_FAST = RM_PREFIX + "fail-fast";

    @Private
    public static final String RM_WORK_PRESERVING_RECOVERY_ENABLED = RM_PREFIX + "work-preserving-recovery.enabled";
    @Private
    public static final boolean DEFAULT_RM_WORK_PRESERVING_RECOVERY_ENABLED = true;

    public static final String RM_WORK_PRESERVING_RECOVERY_SCHEDULING_WAIT_MS = RM_PREFIX
            + "work-preserving-recovery.scheduling-wait-ms";
    public static final long DEFAULT_RM_WORK_PRESERVING_RECOVERY_SCHEDULING_WAIT_MS = 10000;

    /** Zookeeper interaction configs */
    public static final String RM_ZK_PREFIX = RM_PREFIX + "zk-";

    public static final String RM_ZK_ADDRESS = RM_ZK_PREFIX + "address";

    public static final String RM_ZK_NUM_RETRIES = RM_ZK_PREFIX + "num-retries";
    public static final int DEFAULT_ZK_RM_NUM_RETRIES = 1000;

    /** Zookeeper znode limit */
    public static final String RM_ZK_ZNODE_SIZE_LIMIT_BYTES = RM_ZK_PREFIX + "max-znode-size.bytes";
    public static final int DEFAULT_RM_ZK_ZNODE_SIZE_LIMIT_BYTES = 1024 * 1024;

    public static final String RM_ZK_RETRY_INTERVAL_MS = RM_ZK_PREFIX + "retry-interval-ms";
    public static final int DEFAULT_RM_ZK_RETRY_INTERVAL_MS = 1000;

    public static final String RM_ZK_TIMEOUT_MS = RM_ZK_PREFIX + "timeout-ms";
    public static final int DEFAULT_RM_ZK_TIMEOUT_MS = 10000;

    public static final String ZK_APPID_NODE_SPLIT_INDEX = RM_ZK_PREFIX + "appid-node.split-index";
    public static final int DEFAULT_ZK_APPID_NODE_SPLIT_INDEX = 0;

    /** Index at which the RM Delegation Token ids will be split so that the
     * delegation token znodes stored in the zookeeper RM state store will be
     * stored as two different znodes (parent-child). **/
    public static final String ZK_DELEGATION_TOKEN_NODE_SPLIT_INDEX = RM_ZK_PREFIX
            + "delegation-token-node.split-index";
    public static final int DEFAULT_ZK_DELEGATION_TOKEN_NODE_SPLIT_INDEX = 0;

    public static final String RM_ZK_ACL = RM_ZK_PREFIX + "acl";
    public static final String DEFAULT_RM_ZK_ACL = "world:anyone:rwcda";

    public static final String RM_ZK_AUTH = RM_ZK_PREFIX + "auth";

    public static final String ZK_STATE_STORE_PREFIX = RM_PREFIX + "zk-state-store.";

    /** Parent znode path under which ZKRMStateStore will create znodes */
    public static final String ZK_RM_STATE_STORE_PARENT_PATH = ZK_STATE_STORE_PREFIX + "parent-path";
    public static final String DEFAULT_ZK_RM_STATE_STORE_PARENT_PATH = "/rmstore";

    /** Root node ACLs for fencing */
    public static final String ZK_RM_STATE_STORE_ROOT_NODE_ACL = ZK_STATE_STORE_PREFIX + "root-node.acl";

    /** HA related configs */
    public static final String RM_HA_PREFIX = RM_PREFIX + "ha.";
    public static final String RM_HA_ENABLED = RM_HA_PREFIX + "enabled";
    public static final boolean DEFAULT_RM_HA_ENABLED = false;

    public static final String RM_HA_IDS = RM_HA_PREFIX + "rm-ids";
    public static final String RM_HA_ID = RM_HA_PREFIX + "id";

    /** Store the related configuration files in File System */
    public static final String FS_BASED_RM_CONF_STORE = RM_PREFIX + "configuration.file-system-based-store";
    public static final String DEFAULT_FS_BASED_RM_CONF_STORE = "/yarn/conf";

    public static final String RM_CONFIGURATION_PROVIDER_CLASS = RM_PREFIX + "configuration.provider-class";
    public static final String DEFAULT_RM_CONFIGURATION_PROVIDER_CLASS = "org.apache.hadoop.yarn.LocalConfigurationProvider";

    @Private
    @Unstable
    public static final String SCHEDULER_CONFIGURATION_STORE_CLASS = YARN_PREFIX
            + "scheduler.configuration.store.class";
    @Private
    @Unstable
    public static final String FILE_CONFIGURATION_STORE = "file";
    @Private
    @Unstable
    public static final String MEMORY_CONFIGURATION_STORE = "memory";
    @Private
    @Unstable
    public static final String FS_CONFIGURATION_STORE = "fs";
    @Private
    @Unstable
    public static final String ZK_CONFIGURATION_STORE = "zk";
    @Private
    @Unstable
    public static final String LEVELDB_CONFIGURATION_STORE = "leveldb";
    @Private
    @Unstable
    public static final String DEFAULT_CONFIGURATION_STORE = FILE_CONFIGURATION_STORE;
    @Private
    @Unstable
    public static final String RM_SCHEDCONF_STORE_PATH = YARN_PREFIX + "scheduler.configuration.leveldb-store.path";

    @Private
    @Unstable
    public static final String RM_SCHEDCONF_LEVELDB_COMPACTION_INTERVAL_SECS = YARN_PREFIX
            + "scheduler.configuration.leveldb-store.compaction-interval-secs";
    @Private
    @Unstable
    public static final long DEFAULT_RM_SCHEDCONF_LEVELDB_COMPACTION_INTERVAL_SECS = 60 * 60 * 24L;

    @Private
    @Unstable
    public static final String RM_SCHEDCONF_MAX_LOGS = YARN_PREFIX + "scheduler.configuration.store.max-logs";
    @Private
    @Unstable
    public static final long DEFAULT_RM_SCHEDCONF_LEVELDB_MAX_LOGS = 1000;
    @Private
    @Unstable
    public static final long DEFAULT_RM_SCHEDCONF_ZK_MAX_LOGS = 1000;
    @Private
    @Unstable
    public static final String SCHEDULER_CONFIGURATION_FS_PATH = YARN_PREFIX + "scheduler.configuration.fs.path";
    @Private
    @Unstable
    public static final String SCHEDULER_CONFIGURATION_FS_MAX_VERSION = YARN_PREFIX
            + "scheduler.configuration.max.version";
    @Private
    @Unstable
    public static final int DEFAULT_SCHEDULER_CONFIGURATION_FS_MAX_VERSION = 100;

    /** Parent znode path under which ZKConfigurationStore will create znodes. */
    @Private
    @Unstable
    public static final String RM_SCHEDCONF_STORE_ZK_PARENT_PATH = YARN_PREFIX
            + "scheduler.configuration.zk-store.parent-path";
    @Private
    @Unstable
    public static final String DEFAULT_RM_SCHEDCONF_STORE_ZK_PARENT_PATH = "/confstore";

    @Private
    @Unstable
    public static final String RM_SCHEDULER_MUTATION_ACL_POLICY_CLASS = YARN_PREFIX
            + "scheduler.configuration.mutation.acl-policy.class";

    public static final String YARN_AUTHORIZATION_PROVIDER = YARN_PREFIX + "authorization-provider";
    private static final List<String> RM_SERVICES_ADDRESS_CONF_KEYS_HTTP = Collections
            .unmodifiableList(Arrays.asList(RM_ADDRESS, RM_SCHEDULER_ADDRESS, RM_ADMIN_ADDRESS,
                    RM_RESOURCE_TRACKER_ADDRESS, RM_WEBAPP_ADDRESS));

    private static final List<String> RM_SERVICES_ADDRESS_CONF_KEYS_HTTPS = Collections
            .unmodifiableList(Arrays.asList(RM_ADDRESS, RM_SCHEDULER_ADDRESS, RM_ADMIN_ADDRESS,
                    RM_RESOURCE_TRACKER_ADDRESS, RM_WEBAPP_HTTPS_ADDRESS));

    public static final String AUTO_FAILOVER_PREFIX = RM_HA_PREFIX + "automatic-failover.";

    public static final String AUTO_FAILOVER_ENABLED = AUTO_FAILOVER_PREFIX + "enabled";
    public static final boolean DEFAULT_AUTO_FAILOVER_ENABLED = true;

    /**
     * This property controls whether {@link ActiveStandbyElector} leader
     * election should be used when {@link #CURATOR_LEADER_ELECTOR} is
     * {@code false}.
     *
     * @deprecated This property should never be set to {@code false}.
     */
    @Deprecated
    public static final String AUTO_FAILOVER_EMBEDDED = AUTO_FAILOVER_PREFIX + "embedded";
    /**
     * The default value for {@link #AUTO_FAILOVER_EMBEDDED}.
     *
     * @deprecated The {@link #AUTO_FAILOVER_EMBEDDED} property is deprecated.
     */
    @Deprecated
    public static final boolean DEFAULT_AUTO_FAILOVER_EMBEDDED = true;

    public static final String AUTO_FAILOVER_ZK_BASE_PATH = AUTO_FAILOVER_PREFIX + "zk-base-path";
    public static final String DEFAULT_AUTO_FAILOVER_ZK_BASE_PATH = "/yarn-leader-election";

    public static final String CLIENT_FAILOVER_PREFIX = YARN_PREFIX + "client.failover-";
    public static final String CLIENT_FAILOVER_PROXY_PROVIDER = CLIENT_FAILOVER_PREFIX + "proxy-provider";
    public static final String DEFAULT_CLIENT_FAILOVER_PROXY_PROVIDER = "org.apache.hadoop.yarn.client.ConfiguredRMFailoverProxyProvider";

    public static final String CLIENT_FAILOVER_MAX_ATTEMPTS = CLIENT_FAILOVER_PREFIX + "max-attempts";

    public static final String CLIENT_FAILOVER_SLEEPTIME_BASE_MS = CLIENT_FAILOVER_PREFIX + "sleep-base-ms";

    public static final String CLIENT_FAILOVER_SLEEPTIME_MAX_MS = CLIENT_FAILOVER_PREFIX + "sleep-max-ms";

    public static final String CLIENT_FAILOVER_RETRIES = CLIENT_FAILOVER_PREFIX + "retries";
    public static final int DEFAULT_CLIENT_FAILOVER_RETRIES = 0;

    public static final String CLIENT_FAILOVER_RETRIES_ON_SOCKET_TIMEOUTS = CLIENT_FAILOVER_PREFIX
            + "retries-on-socket-timeouts";
    public static final int DEFAULT_CLIENT_FAILOVER_RETRIES_ON_SOCKET_TIMEOUTS = 0;

    /** number of zookeeper operation retry times in ActiveStandbyElector */
    public static final String RM_HA_FC_ELECTOR_ZK_RETRIES_KEY = RM_HA_PREFIX
            + "failover-controller.active-standby-elector.zk.retries";

    /**
     * Whether to use the Curator-based elector for leader election.
     *
     * @deprecated Eventually, we want to default to the curator-based
     * implementation and remove the {@link ActiveStandbyElector} based
     * implementation. We should remove this config then.
     */
    @Unstable
    @Deprecated
    public static final String CURATOR_LEADER_ELECTOR = RM_HA_PREFIX + "curator-leader-elector.enabled";
    @Private
    @Unstable
    public static final boolean DEFAULT_CURATOR_LEADER_ELECTOR_ENABLED = false;

    ////////////////////////////////
    // RM state store configs
    ////////////////////////////////
    /** The class to use as the persistent store.*/
    public static final String RM_STORE = RM_PREFIX + "store.class";

    /** URI for FileSystemRMStateStore */
    public static final String FS_RM_STATE_STORE_URI = RM_PREFIX + "fs.state-store.uri";

    public static final String FS_RM_STATE_STORE_NUM_RETRIES = RM_PREFIX + "fs.state-store.num-retries";
    public static final int DEFAULT_FS_RM_STATE_STORE_NUM_RETRIES = 0;

    public static final String FS_RM_STATE_STORE_RETRY_INTERVAL_MS = RM_PREFIX + "fs.state-store.retry-interval-ms";
    public static final long DEFAULT_FS_RM_STATE_STORE_RETRY_INTERVAL_MS = 1000L;

    public static final String RM_LEVELDB_STORE_PATH = RM_PREFIX + "leveldb-state-store.path";

    /** The time in seconds between full compactions of the leveldb database.
     *  Setting the interval to zero disables the full compaction cycles.
     */
    public static final String RM_LEVELDB_COMPACTION_INTERVAL_SECS = RM_PREFIX
            + "leveldb-state-store.compaction-interval-secs";
    public static final long DEFAULT_RM_LEVELDB_COMPACTION_INTERVAL_SECS = 3600;

    /**
     * The maximum number of completed applications RM keeps. By default equals
     * to {@link #DEFAULT_RM_MAX_COMPLETED_APPLICATIONS}.
     */
    public static final String RM_MAX_COMPLETED_APPLICATIONS = RM_PREFIX + "max-completed-applications";
    public static final int DEFAULT_RM_MAX_COMPLETED_APPLICATIONS = 1000;

    /**
     * The maximum number of completed applications RM state store keeps. By
     * default equals to value of {@link #RM_MAX_COMPLETED_APPLICATIONS}.
     */
    public static final String RM_STATE_STORE_MAX_COMPLETED_APPLICATIONS = RM_PREFIX
            + "state-store.max-completed-applications";
    /**
     * The default value for
     * {@code yarn.resourcemanager.state-store.max-completed-applications}.
     * @deprecated This default value is ignored and will be removed in a future
     * release. The default value of
     * {@code yarn.resourcemanager.state-store.max-completed-applications} is the
     * value of {@link #RM_MAX_COMPLETED_APPLICATIONS}.
     */
    @Deprecated
    public static final int DEFAULT_RM_STATE_STORE_MAX_COMPLETED_APPLICATIONS = DEFAULT_RM_MAX_COMPLETED_APPLICATIONS;

    /** Default application name */
    public static final String DEFAULT_APPLICATION_NAME = "N/A";

    /** Default application type */
    public static final String DEFAULT_APPLICATION_TYPE = "YARN";

    /** Default application type length */
    public static final int APPLICATION_TYPE_LENGTH = 20;

    /** Default queue name */
    public static final String DEFAULT_QUEUE_NAME = "default";

    /**
     * Buckets (in minutes) for the number of apps running in each queue.
     */
    public static final String RM_METRICS_RUNTIME_BUCKETS = RM_PREFIX + "metrics.runtime.buckets";

    /**
     * Default sizes of the runtime metric buckets in minutes.
     */
    public static final String DEFAULT_RM_METRICS_RUNTIME_BUCKETS = "60,300,1440";

    public static final String RM_AMRM_TOKEN_MASTER_KEY_ROLLING_INTERVAL_SECS = RM_PREFIX
            + "am-rm-tokens.master-key-rolling-interval-secs";

    public static final long DEFAULT_RM_AMRM_TOKEN_MASTER_KEY_ROLLING_INTERVAL_SECS = 24 * 60 * 60;

    public static final String RM_CONTAINER_TOKEN_MASTER_KEY_ROLLING_INTERVAL_SECS = RM_PREFIX
            + "container-tokens.master-key-rolling-interval-secs";

    public static final long DEFAULT_RM_CONTAINER_TOKEN_MASTER_KEY_ROLLING_INTERVAL_SECS = 24 * 60 * 60;

    public static final String RM_NMTOKEN_MASTER_KEY_ROLLING_INTERVAL_SECS = RM_PREFIX
            + "nm-tokens.master-key-rolling-interval-secs";

    public static final long DEFAULT_RM_NMTOKEN_MASTER_KEY_ROLLING_INTERVAL_SECS = 24 * 60 * 60;

    public static final String RM_NODEMANAGER_MINIMUM_VERSION = RM_PREFIX + "nodemanager.minimum.version";

    public static final String DEFAULT_RM_NODEMANAGER_MINIMUM_VERSION = "NONE";

    /**
     * Timeout(msec) for an untracked node to remain in shutdown or decommissioned
     * state.
     */
    public static final String RM_NODEMANAGER_UNTRACKED_REMOVAL_TIMEOUT_MSEC = RM_PREFIX
            + "node-removal-untracked.timeout-ms";
    public static final int DEFAULT_RM_NODEMANAGER_UNTRACKED_REMOVAL_TIMEOUT_MSEC = 60000;

    /**
     * RM proxy users' prefix
     */
    public static final String RM_PROXY_USER_PREFIX = RM_PREFIX + "proxyuser.";

    /**
     * Enable/disable resource profiles.
     */
    @Public
    @Unstable
    public static final String RM_RESOURCE_PROFILES_ENABLED = RM_PREFIX + "resource-profiles.enabled";
    @Public
    @Unstable
    public static final boolean DEFAULT_RM_RESOURCE_PROFILES_ENABLED = false;

    /**
     * File containing resource profiles.
     */
    @Public
    @Unstable
    public static final String RM_RESOURCE_PROFILES_SOURCE_FILE = RM_PREFIX + "resource-profiles.source-file";
    @Public
    @Unstable
    public static final String DEFAULT_RM_RESOURCE_PROFILES_SOURCE_FILE = "resource-profiles.json";

    /**
     * Enable/disable loading resource-types.xml at client side.
     */
    @Public
    @Unstable
    public static final String YARN_CLIENT_LOAD_RESOURCETYPES_FROM_SERVER = YARN_PREFIX
            + "client.load.resource-types.from-server";
    @Public
    @Unstable
    public static final boolean DEFAULT_YARN_CLIENT_LOAD_RESOURCETYPES_FROM_SERVER = false;

    /**
     * Timeout in seconds for YARN node graceful decommission.
     * This is the maximal time to wait for running containers and applications
     * to complete before transition a DECOMMISSIONING node into DECOMMISSIONED.
     */
    public static final String RM_NODE_GRACEFUL_DECOMMISSION_TIMEOUT = RM_PREFIX
            + "nodemanager-graceful-decommission-timeout-secs";
    public static final int DEFAULT_RM_NODE_GRACEFUL_DECOMMISSION_TIMEOUT = 3600;

    /**
     * Period in seconds of the poll timer task inside DecommissioningNodesWatcher
     * to identify and take care of DECOMMISSIONING nodes missing regular heart beat.
     */
    public static final String RM_DECOMMISSIONING_NODES_WATCHER_POLL_INTERVAL = RM_PREFIX
            + "decommissioning-nodes-watcher.poll-interval-secs";
    public static final int DEFAULT_RM_DECOMMISSIONING_NODES_WATCHER_POLL_INTERVAL = 20;

    ////////////////////////////////
    // Node Manager Configs
    ////////////////////////////////

    /** Prefix for all node manager configs.*/
    public static final String NM_PREFIX = "yarn.nodemanager.";

    /** Max Queue length of <code>OPPORTUNISTIC</code> containers on the NM. */
    public static final String NM_OPPORTUNISTIC_CONTAINERS_MAX_QUEUE_LENGTH = NM_PREFIX
            + "opportunistic-containers-max-queue-length";
    public static final int DEFAULT_NM_OPPORTUNISTIC_CONTAINERS_MAX_QUEUE_LENGTH = 0;

    /** Setting that controls whether distributed scheduling is enabled or not. */
    public static final String DIST_SCHEDULING_ENABLED = NM_PREFIX + "distributed-scheduling.enabled";
    public static final boolean DEFAULT_DIST_SCHEDULING_ENABLED = false;

    /** Environment variables that will be sent to containers.*/
    public static final String NM_ADMIN_USER_ENV = NM_PREFIX + "admin-env";
    public static final String DEFAULT_NM_ADMIN_USER_ENV = "MALLOC_ARENA_MAX=$MALLOC_ARENA_MAX";

    /** Environment variables that containers may override rather than use NodeManager's default.*/
    public static final String NM_ENV_WHITELIST = NM_PREFIX + "env-whitelist";
    public static final String DEFAULT_NM_ENV_WHITELIST = StringUtils.join(",",
            Arrays.asList(ApplicationConstants.Environment.JAVA_HOME.key(),
                    ApplicationConstants.Environment.HADOOP_COMMON_HOME.key(),
                    ApplicationConstants.Environment.HADOOP_HDFS_HOME.key(),
                    ApplicationConstants.Environment.HADOOP_CONF_DIR.key(),
                    ApplicationConstants.Environment.CLASSPATH_PREPEND_DISTCACHE.key(),
                    ApplicationConstants.Environment.HADOOP_YARN_HOME.key()));

    /** address of node manager IPC.*/
    public static final String NM_ADDRESS = NM_PREFIX + "address";
    public static final int DEFAULT_NM_PORT = 0;
    public static final String DEFAULT_NM_ADDRESS = "0.0.0.0:" + DEFAULT_NM_PORT;

    /** The actual bind address for the NM.*/
    public static final String NM_BIND_HOST = NM_PREFIX + "bind-host";

    /** who will execute(launch) the containers.*/
    public static final String NM_CONTAINER_EXECUTOR = NM_PREFIX + "container-executor.class";

    /** List of container state transition listeners.*/
    public static final String NM_CONTAINER_STATE_TRANSITION_LISTENERS = NM_PREFIX
            + "container-state-transition-listener.classes";

    /**  
     * Adjustment to make to the container os scheduling priority.
     * The valid values for this could vary depending on the platform.
     * On Linux, higher values mean run the containers at a less 
     * favorable priority than the NM. 
     * The value specified is an int.
     */
    public static final String NM_CONTAINER_EXECUTOR_SCHED_PRIORITY = NM_PREFIX
            + "container-executor.os.sched.priority.adjustment";
    public static final int DEFAULT_NM_CONTAINER_EXECUTOR_SCHED_PRIORITY = 0;

    /** Number of threads container manager uses.*/
    public static final String NM_CONTAINER_MGR_THREAD_COUNT = NM_PREFIX + "container-manager.thread-count";
    public static final int DEFAULT_NM_CONTAINER_MGR_THREAD_COUNT = 20;

    /** Number of threads container manager uses.*/
    public static final String NM_COLLECTOR_SERVICE_THREAD_COUNT = NM_PREFIX + "collector-service.thread-count";
    public static final int DEFAULT_NM_COLLECTOR_SERVICE_THREAD_COUNT = 5;

    /** Number of threads used in cleanup.*/
    public static final String NM_DELETE_THREAD_COUNT = NM_PREFIX + "delete.thread-count";
    public static final int DEFAULT_NM_DELETE_THREAD_COUNT = 4;

    /** Keytab for NM.*/
    public static final String NM_KEYTAB = NM_PREFIX + "keytab";

    /**List of directories to store localized files in.*/
    public static final String NM_LOCAL_DIRS = NM_PREFIX + "local-dirs";
    public static final String DEFAULT_NM_LOCAL_DIRS = "/tmp/nm-local-dir";

    /**
     * Number of files in each localized directories
     * Avoid tuning this too low. 
     */
    public static final String NM_LOCAL_CACHE_MAX_FILES_PER_DIRECTORY = NM_PREFIX
            + "local-cache.max-files-per-directory";
    public static final int DEFAULT_NM_LOCAL_CACHE_MAX_FILES_PER_DIRECTORY = 8192;

    /** Address where the localizer IPC is.*/
    public static final String NM_LOCALIZER_ADDRESS = NM_PREFIX + "localizer.address";
    public static final int DEFAULT_NM_LOCALIZER_PORT = 8040;
    public static final String DEFAULT_NM_LOCALIZER_ADDRESS = "0.0.0.0:" + DEFAULT_NM_LOCALIZER_PORT;

    /** Address where the collector service IPC is.*/
    public static final String NM_COLLECTOR_SERVICE_ADDRESS = NM_PREFIX + "collector-service.address";
    public static final int DEFAULT_NM_COLLECTOR_SERVICE_PORT = 8048;
    public static final String DEFAULT_NM_COLLECTOR_SERVICE_ADDRESS = "0.0.0.0:"
            + DEFAULT_NM_COLLECTOR_SERVICE_PORT;

    /** Interval in between cache cleanups.*/
    public static final String NM_LOCALIZER_CACHE_CLEANUP_INTERVAL_MS = NM_PREFIX
            + "localizer.cache.cleanup.interval-ms";
    public static final long DEFAULT_NM_LOCALIZER_CACHE_CLEANUP_INTERVAL_MS = 10 * 60 * 1000;

    /**
     * Target size of localizer cache in MB, per nodemanager. It is a target
     * retention size that only includes resources with PUBLIC and PRIVATE
     * visibility and excludes resources with APPLICATION visibility
     */
    public static final String NM_LOCALIZER_CACHE_TARGET_SIZE_MB = NM_PREFIX + "localizer.cache.target-size-mb";
    public static final long DEFAULT_NM_LOCALIZER_CACHE_TARGET_SIZE_MB = 10 * 1024;

    /** Number of threads to handle localization requests.*/
    public static final String NM_LOCALIZER_CLIENT_THREAD_COUNT = NM_PREFIX + "localizer.client.thread-count";
    public static final int DEFAULT_NM_LOCALIZER_CLIENT_THREAD_COUNT = 5;

    /** Number of threads to use for localization fetching.*/
    public static final String NM_LOCALIZER_FETCH_THREAD_COUNT = NM_PREFIX + "localizer.fetch.thread-count";
    public static final int DEFAULT_NM_LOCALIZER_FETCH_THREAD_COUNT = 4;

    /** Where to store container logs.*/
    public static final String NM_LOG_DIRS = NM_PREFIX + "log-dirs";
    public static final String DEFAULT_NM_LOG_DIRS = "/tmp/logs";

    /** The number of threads to handle log aggregation in node manager. */
    public static final String NM_LOG_AGGREGATION_THREAD_POOL_SIZE = NM_PREFIX
            + "logaggregation.threadpool-size-max";
    public static final int DEFAULT_NM_LOG_AGGREGATION_THREAD_POOL_SIZE = 100;

    /** Default permissions for container logs. */
    public static final String NM_DEFAULT_CONTAINER_EXECUTOR_PREFIX = NM_PREFIX + "default-container-executor.";
    public static final String NM_DEFAULT_CONTAINER_EXECUTOR_LOG_DIRS_PERMISSIONS = NM_DEFAULT_CONTAINER_EXECUTOR_PREFIX
            + "log-dirs.permissions";
    public static final String NM_DEFAULT_CONTAINER_EXECUTOR_LOG_DIRS_PERMISSIONS_DEFAULT = "710";

    public static final String NM_RESOURCEMANAGER_MINIMUM_VERSION = NM_PREFIX + "resourcemanager.minimum.version";
    public static final String DEFAULT_NM_RESOURCEMANAGER_MINIMUM_VERSION = "NONE";

    /** Disk Validator. */
    public static final String DISK_VALIDATOR = NM_PREFIX + "disk-validator";
    public static final String DEFAULT_DISK_VALIDATOR = BasicDiskValidator.NAME;

    /**
     * Maximum size of contain's diagnostics to keep for relaunching container
     * case.
     **/
    public static final String NM_CONTAINER_DIAGNOSTICS_MAXIMUM_SIZE = NM_PREFIX
            + "container-diagnostics-maximum-size";
    public static final int DEFAULT_NM_CONTAINER_DIAGNOSTICS_MAXIMUM_SIZE = 10000;

    /** Minimum container restart interval. */
    public static final String NM_CONTAINER_RETRY_MINIMUM_INTERVAL_MS = NM_PREFIX
            + "container-retry-minimum-interval-ms";
    public static final int DEFAULT_NM_CONTAINER_RETRY_MINIMUM_INTERVAL_MS = 1000;

    /**
     * Use container pause as the preemption policy over kill in the container
     * queue at a NodeManager.
     **/
    public static final String NM_CONTAINER_QUEUING_USE_PAUSE_FOR_PREEMPTION = NM_PREFIX
            + "opportunistic-containers-use-pause-for-preemption";
    public static final boolean DEFAULT_NM_CONTAINER_QUEUING_USE_PAUSE_FOR_PREEMPTION = false;

    /** Interval at which the delayed token removal thread runs */
    public static final String RM_DELAYED_DELEGATION_TOKEN_REMOVAL_INTERVAL_MS = RM_PREFIX
            + "delayed.delegation-token.removal-interval-ms";
    public static final long DEFAULT_RM_DELAYED_DELEGATION_TOKEN_REMOVAL_INTERVAL_MS = 30000l;

    /** Delegation Token renewer thread count */
    public static final String RM_DELEGATION_TOKEN_RENEWER_THREAD_COUNT = RM_PREFIX
            + "delegation-token-renewer.thread-count";
    public static final int DEFAULT_RM_DELEGATION_TOKEN_RENEWER_THREAD_COUNT = 50;

    public static final String RM_PROXY_USER_PRIVILEGES_ENABLED = RM_PREFIX + "proxy-user-privileges.enabled";
    public static final boolean DEFAULT_RM_PROXY_USER_PRIVILEGES_ENABLED = false;

    /** The expiry interval for node IP caching. -1 disables the caching */
    public static final String RM_NODE_IP_CACHE_EXPIRY_INTERVAL_SECS = RM_PREFIX
            + "node-ip-cache.expiry-interval-secs";
    public static final int DEFAULT_RM_NODE_IP_CACHE_EXPIRY_INTERVAL_SECS = -1;

    /**
     * How many diagnostics/failure messages can be saved in RM for
     * log aggregation. It also defines the number of diagnostics/failure
     * messages can be shown in log aggregation web ui.
     */
    public static final String RM_MAX_LOG_AGGREGATION_DIAGNOSTICS_IN_MEMORY = RM_PREFIX
            + "max-log-aggregation-diagnostics-in-memory";
    public static final int DEFAULT_RM_MAX_LOG_AGGREGATION_DIAGNOSTICS_IN_MEMORY = 10;

    /** Whether to enable log aggregation */
    public static final String LOG_AGGREGATION_ENABLED = YARN_PREFIX + "log-aggregation-enable";
    public static final boolean DEFAULT_LOG_AGGREGATION_ENABLED = false;

    public static final String LOG_AGGREGATION_FILE_FORMATS = YARN_PREFIX + "log-aggregation.file-formats";
    public static final String LOG_AGGREGATION_FILE_CONTROLLER_FMT = YARN_PREFIX
            + "log-aggregation.file-controller.%s.class";

    public static final String LOG_AGGREGATION_REMOTE_APP_LOG_DIR_FMT = YARN_PREFIX
            + "log-aggregation.%s.remote-app-log-dir";
    public static final String LOG_AGGREGATION_REMOTE_APP_LOG_DIR_SUFFIX_FMT = YARN_PREFIX
            + "log-aggregation.%s.remote-app-log-dir-suffix";

    /** 
     * How long to wait before deleting aggregated logs, -1 disables.
     * Be careful set this too small and you will spam the name node.
     */
    public static final String LOG_AGGREGATION_RETAIN_SECONDS = YARN_PREFIX + "log-aggregation.retain-seconds";
    public static final long DEFAULT_LOG_AGGREGATION_RETAIN_SECONDS = -1;

    /**
     * How long to wait between aggregated log retention checks. If set to
     * a value {@literal <=} 0 then the value is computed as one-tenth of the
     * log retention setting. Be careful set this too small and you will spam
     * the name node.
     */
    public static final String LOG_AGGREGATION_RETAIN_CHECK_INTERVAL_SECONDS = YARN_PREFIX
            + "log-aggregation.retain-check-interval-seconds";
    public static final long DEFAULT_LOG_AGGREGATION_RETAIN_CHECK_INTERVAL_SECONDS = -1;

    /**
     * How long for ResourceManager to wait for NodeManager to report its
     * log aggregation status. If waiting time of which the log aggregation status
     * is reported from NodeManager exceeds the configured value, RM will report
     * log aggregation status for this NodeManager as TIME_OUT.
     *
     * This configuration will be used in NodeManager as well to decide
     * whether and when to delete the cached log aggregation status.
     */
    public static final String LOG_AGGREGATION_STATUS_TIME_OUT_MS = YARN_PREFIX
            + "log-aggregation-status.time-out.ms";
    public static final long DEFAULT_LOG_AGGREGATION_STATUS_TIME_OUT_MS = 10 * 60 * 1000;

    /**
     * Number of seconds to retain logs on the NodeManager. Only applicable if Log
     * aggregation is disabled
     */
    public static final String NM_LOG_RETAIN_SECONDS = NM_PREFIX + "log.retain-seconds";
    public static final long DEFAULT_NM_LOG_RETAIN_SECONDS = 3 * 60 * 60;

    /**
     * Define how often NMs wake up and upload log files
     */
    public static final String NM_LOG_AGGREGATION_ROLL_MONITORING_INTERVAL_SECONDS = NM_PREFIX
            + "log-aggregation.roll-monitoring-interval-seconds";
    public static final long DEFAULT_NM_LOG_AGGREGATION_ROLL_MONITORING_INTERVAL_SECONDS = -1;

    /**
     * Define how many aggregated log files per application per NM we can have
     * in remote file system.
     */
    public static final String NM_LOG_AGGREGATION_NUM_LOG_FILES_SIZE_PER_APP = NM_PREFIX
            + "log-aggregation.num-log-files-per-app";
    public static final int DEFAULT_NM_LOG_AGGREGATION_NUM_LOG_FILES_SIZE_PER_APP = 30;

    /**
     * Number of threads used in log cleanup. Only applicable if Log aggregation
     * is disabled
     */
    public static final String NM_LOG_DELETION_THREADS_COUNT = NM_PREFIX + "log.deletion-threads-count";
    public static final int DEFAULT_NM_LOG_DELETE_THREAD_COUNT = 4;

    /** Where to aggregate logs to.*/
    public static final String NM_REMOTE_APP_LOG_DIR = NM_PREFIX + "remote-app-log-dir";
    public static final String DEFAULT_NM_REMOTE_APP_LOG_DIR = "/tmp/logs";

    /**
     * The remote log dir will be created at
     * NM_REMOTE_APP_LOG_DIR/${user}/NM_REMOTE_APP_LOG_DIR_SUFFIX/${appId}
     */
    public static final String NM_REMOTE_APP_LOG_DIR_SUFFIX = NM_PREFIX + "remote-app-log-dir-suffix";
    public static final String DEFAULT_NM_REMOTE_APP_LOG_DIR_SUFFIX = "logs";

    public static final String YARN_LOG_SERVER_URL = YARN_PREFIX + "log.server.url";

    public static final String YARN_LOG_SERVER_WEBSERVICE_URL = YARN_PREFIX + "log.server.web-service.url";

    public static final String YARN_TRACKING_URL_GENERATOR = YARN_PREFIX + "tracking.url.generator";

    /** Amount of memory in MB that can be allocated for containers.*/
    public static final String NM_PMEM_MB = NM_PREFIX + "resource.memory-mb";
    public static final int DEFAULT_NM_PMEM_MB = 8 * 1024;

    /** Amount of memory in MB that has been reserved for non-yarn use. */
    public static final String NM_SYSTEM_RESERVED_PMEM_MB = NM_PREFIX + "resource.system-reserved-memory-mb";

    /** Specifies whether physical memory check is enabled. */
    public static final String NM_PMEM_CHECK_ENABLED = NM_PREFIX + "pmem-check-enabled";
    public static final boolean DEFAULT_NM_PMEM_CHECK_ENABLED = true;

    /** Specifies whether physical memory check is enabled. */
    public static final String NM_VMEM_CHECK_ENABLED = NM_PREFIX + "vmem-check-enabled";
    public static final boolean DEFAULT_NM_VMEM_CHECK_ENABLED = true;

    /** Conversion ratio for physical memory to virtual memory. */
    public static final String NM_VMEM_PMEM_RATIO = NM_PREFIX + "vmem-pmem-ratio";
    public static final float DEFAULT_NM_VMEM_PMEM_RATIO = 2.1f;

    /** Specifies whether to do memory check on overall usage. */
    public static final String NM_ELASTIC_MEMORY_CONTROL_ENABLED = NM_PREFIX + "elastic-memory-control.enabled";
    public static final boolean DEFAULT_NM_ELASTIC_MEMORY_CONTROL_ENABLED = false;

    /** Specifies the OOM handler code. */
    public static final String NM_ELASTIC_MEMORY_CONTROL_OOM_HANDLER = NM_PREFIX
            + "elastic-memory-control.oom-handler";

    /** The path to the OOM listener.*/
    public static final String NM_ELASTIC_MEMORY_CONTROL_OOM_LISTENER_PATH = NM_PREFIX
            + "elastic-memory-control.oom-listener.path";

    /** Maximum time in seconds to resolve an OOM situation. */
    public static final String NM_ELASTIC_MEMORY_CONTROL_OOM_TIMEOUT_SEC = NM_PREFIX
            + "elastic-memory-control.timeout-sec";
    public static final Integer DEFAULT_NM_ELASTIC_MEMORY_CONTROL_OOM_TIMEOUT_SEC = 5;

    /** Number of Virtual CPU Cores which can be allocated for containers.*/
    public static final String NM_VCORES = NM_PREFIX + "resource.cpu-vcores";
    public static final int DEFAULT_NM_VCORES = 8;

    /** Count logical processors(like hyperthreads) as cores. */
    public static final String NM_COUNT_LOGICAL_PROCESSORS_AS_CORES = NM_PREFIX
            + "resource.count-logical-processors-as-cores";
    public static final boolean DEFAULT_NM_COUNT_LOGICAL_PROCESSORS_AS_CORES = false;

    /** Multiplier to convert physical cores to vcores. */
    public static final String NM_PCORES_VCORES_MULTIPLIER = NM_PREFIX + "resource.pcores-vcores-multiplier";
    public static final float DEFAULT_NM_PCORES_VCORES_MULTIPLIER = 1.0f;

    /** Percentage of overall CPU which can be allocated for containers. */
    public static final String NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT = NM_PREFIX
            + "resource.percentage-physical-cpu-limit";
    public static final int DEFAULT_NM_RESOURCE_PERCENTAGE_PHYSICAL_CPU_LIMIT = 100;

    /** Enable or disable node hardware capability detection. */
    public static final String NM_ENABLE_HARDWARE_CAPABILITY_DETECTION = NM_PREFIX
            + "resource.detect-hardware-capabilities";
    public static final boolean DEFAULT_NM_ENABLE_HARDWARE_CAPABILITY_DETECTION = false;

    @Private
    public static final String NM_MEMORY_RESOURCE_PREFIX = NM_PREFIX + "resource.memory.";

    public static final String NM_MEMORY_RESOURCE_ENABLED = NM_MEMORY_RESOURCE_PREFIX + "enabled";
    public static final boolean DEFAULT_NM_MEMORY_RESOURCE_ENABLED = false;

    public static final String NM_MEMORY_RESOURCE_ENFORCED = NM_MEMORY_RESOURCE_PREFIX + "enforced";
    public static final boolean DEFAULT_NM_MEMORY_RESOURCE_ENFORCED = true;

    public static final String NM_MEMORY_RESOURCE_CGROUPS_SWAPPINESS = NM_MEMORY_RESOURCE_PREFIX
            + "cgroups.swappiness";
    public static final int DEFAULT_NM_MEMORY_RESOURCE_CGROUPS_SWAPPINESS = 0;

    public static final String NM_MEMORY_RESOURCE_CGROUPS_SOFT_LIMIT_PERCENTAGE = NM_MEMORY_RESOURCE_PREFIX
            + "cgroups.soft-limit-percentage";
    public static final float DEFAULT_NM_MEMORY_RESOURCE_CGROUPS_SOFT_LIMIT_PERCENTAGE = 90.0f;

    @Private
    public static final String NM_CPU_RESOURCE_PREFIX = NM_PREFIX + "resource.cpu.";

    /** Enable cpu isolation. */
    @Private
    public static final String NM_CPU_RESOURCE_ENABLED = NM_CPU_RESOURCE_PREFIX + "enabled";

    @Private
    public static final boolean DEFAULT_NM_CPU_RESOURCE_ENABLED = false;

    /**
     * Prefix for disk configurations. Work in progress: This configuration
     * parameter may be changed/removed in the future.
     */
    @Private
    public static final String NM_DISK_RESOURCE_PREFIX = NM_PREFIX + "resource.disk.";
    /**
     * This setting controls if resource handling for disk operations is enabled.
     * Work in progress: This configuration parameter may be changed/removed in
     * the future
     */
    @Private
    public static final String NM_DISK_RESOURCE_ENABLED = NM_DISK_RESOURCE_PREFIX + "enabled";
    /** Disk as a resource is disabled by default. **/
    @Private
    public static final boolean DEFAULT_NM_DISK_RESOURCE_ENABLED = false;

    public static final String NM_NETWORK_RESOURCE_PREFIX = NM_PREFIX + "resource.network.";

    /**
     * This setting controls if resource handling for network bandwidth is
     * enabled. Work in progress: This configuration parameter may be
     * changed/removed in the future
     */
    @Private
    public static final String NM_NETWORK_RESOURCE_ENABLED = NM_NETWORK_RESOURCE_PREFIX + "enabled";
    /** Network as a resource is disabled by default. **/
    @Private
    public static final boolean DEFAULT_NM_NETWORK_RESOURCE_ENABLED = false;

    /**
     * Specifies the interface to be used for applying network throttling rules.
     * Work in progress: This configuration parameter may be changed/removed in
     * the future
     */
    @Private
    public static final String NM_NETWORK_RESOURCE_INTERFACE = NM_NETWORK_RESOURCE_PREFIX + "interface";
    @Private
    public static final String DEFAULT_NM_NETWORK_RESOURCE_INTERFACE = "eth0";

    /**
     * Specifies the total available outbound bandwidth on the node. Work in
     * progress: This configuration parameter may be changed/removed in the future
     */
    @Private
    public static final String NM_NETWORK_RESOURCE_OUTBOUND_BANDWIDTH_MBIT = NM_NETWORK_RESOURCE_PREFIX
            + "outbound-bandwidth-mbit";
    @Private
    public static final int DEFAULT_NM_NETWORK_RESOURCE_OUTBOUND_BANDWIDTH_MBIT = 1000;

    /**
     * Specifies the total outbound bandwidth available to YARN containers.
     * defaults to NM_NETWORK_RESOURCE_OUTBOUND_BANDWIDTH_MBIT if not specified.
     * Work in progress: This configuration parameter may be changed/removed in
     * the future
     */
    @Private
    public static final String NM_NETWORK_RESOURCE_OUTBOUND_BANDWIDTH_YARN_MBIT = NM_NETWORK_RESOURCE_PREFIX
            + "outbound-bandwidth-yarn-mbit";

    /**
     * Prefix for computation resources, example of computation resources like
     * GPU / FPGA / TPU, etc.
     */
    @Private
    public static final String NM_RESOURCE_PLUGINS = NM_PREFIX + "resource-plugins";

    /**
     * Prefix for gpu configurations. Work in progress: This configuration
     * parameter may be changed/removed in the future.
     */
    @Private
    public static final String NM_GPU_RESOURCE_PREFIX = NM_RESOURCE_PLUGINS + ".gpu.";

    @Private
    public static final String NM_GPU_ALLOWED_DEVICES = NM_GPU_RESOURCE_PREFIX + "allowed-gpu-devices";
    @Private
    public static final String AUTOMATICALLY_DISCOVER_GPU_DEVICES = "auto";

    /**
     * This setting controls where to how to invoke GPU binaries
     */
    @Private
    public static final String NM_GPU_PATH_TO_EXEC = NM_GPU_RESOURCE_PREFIX + "path-to-discovery-executables";

    @Private
    public static final String DEFAULT_NM_GPU_PATH_TO_EXEC = "";

    /**
     * Settings to control which implementation of docker plugin for GPU will be
     * used.
     *
     * By default uses NVIDIA docker v1.
     */
    @Private
    public static final String NM_GPU_DOCKER_PLUGIN_IMPL = NM_GPU_RESOURCE_PREFIX + "docker-plugin";

    @Private
    public static final String NVIDIA_DOCKER_V1 = "nvidia-docker-v1";

    @Private
    public static final String NVIDIA_DOCKER_V2 = "nvidia-docker-v2";

    @Private
    public static final String DEFAULT_NM_GPU_DOCKER_PLUGIN_IMPL = NVIDIA_DOCKER_V1;

    /**
     * This setting controls end point of nvidia-docker-v1 plugin
     */
    @Private
    public static final String NVIDIA_DOCKER_PLUGIN_V1_ENDPOINT = NM_GPU_RESOURCE_PREFIX + "docker-plugin."
            + NVIDIA_DOCKER_V1 + ".endpoint";

    @Private
    public static final String DEFAULT_NVIDIA_DOCKER_PLUGIN_V1_ENDPOINT = "http://localhost:3476/v1.0/docker/cli";

    /**
     * Prefix for FPGA configurations. Work in progress: This configuration
     * parameter may be changed/removed in the future.
     */
    @Private
    public static final String NM_FPGA_RESOURCE_PREFIX = NM_RESOURCE_PLUGINS + ".fpga.";

    @Private
    public static final String NM_FPGA_ALLOWED_DEVICES = NM_FPGA_RESOURCE_PREFIX + "allowed-fpga-devices";

    @Private
    public static final String NM_FPGA_PATH_TO_EXEC = NM_FPGA_RESOURCE_PREFIX + "path-to-discovery-executables";

    @Private
    public static final String NM_FPGA_VENDOR_PLUGIN = NM_FPGA_RESOURCE_PREFIX + "vendor-plugin.class";

    @Private
    public static final String DEFAULT_NM_FPGA_VENDOR_PLUGIN = "org.apache.hadoop.yarn.server.nodemanager.containermanager.resourceplugin.fpga.IntelFpgaOpenclPlugin";

    public static final String NM_NETWORK_TAG_PREFIX = NM_PREFIX + "network-tagging";

    public static final String NM_NETWORK_TAG_HANDLER_ENABLED = NM_NETWORK_TAG_PREFIX + "-handler.enabled";

    public static final boolean DEFAULT_NM_NETWORK_TAG_HANDLER_ENABLED = false;

    public static final String NM_NETWORK_TAG_MAPPING_MANAGER = NM_NETWORK_TAG_PREFIX + ".mapping-mamager.class";

    public static final String NM_NETWORK_TAG_MAPPING_FILE_PATH = NM_NETWORK_TAG_PREFIX + ".mapping-file.path";

    public static final String DEFAULT_NM_NETWORK_RESOURCE_TAG_MAPPING_FILE_PATH = "";

    /** NM Webapp address.**/
    public static final String NM_WEBAPP_ADDRESS = NM_PREFIX + "webapp.address";
    public static final int DEFAULT_NM_WEBAPP_PORT = 8042;
    public static final String DEFAULT_NM_WEBAPP_ADDRESS = "0.0.0.0:" + DEFAULT_NM_WEBAPP_PORT;

    /** NM Webapp https address.**/
    public static final String NM_WEBAPP_HTTPS_ADDRESS = NM_PREFIX + "webapp.https.address";
    public static final int DEFAULT_NM_WEBAPP_HTTPS_PORT = 8044;
    public static final String DEFAULT_NM_WEBAPP_HTTPS_ADDRESS = "0.0.0.0:" + DEFAULT_NM_WEBAPP_HTTPS_PORT;

    /** Enable/disable CORS filter. */
    public static final String NM_WEBAPP_ENABLE_CORS_FILTER = NM_PREFIX + "webapp.cross-origin.enabled";
    public static final boolean DEFAULT_NM_WEBAPP_ENABLE_CORS_FILTER = false;

    /** How often to monitor resource in a node.*/
    public static final String NM_RESOURCE_MON_INTERVAL_MS = NM_PREFIX + "resource-monitor.interval-ms";
    public static final int DEFAULT_NM_RESOURCE_MON_INTERVAL_MS = 3000;

    public static final String NM_CONTAINER_MONITOR_ENABLED = NM_PREFIX + "container-monitor.enabled";
    public static final boolean DEFAULT_NM_CONTAINER_MONITOR_ENABLED = true;

    /** How often to monitor containers.*/
    public final static String NM_CONTAINER_MON_INTERVAL_MS = NM_PREFIX + "container-monitor.interval-ms";
    @Deprecated
    public final static int DEFAULT_NM_CONTAINER_MON_INTERVAL_MS = 3000;

    /** Class that calculates current resource utilization.*/
    public static final String NM_MON_RESOURCE_CALCULATOR = NM_PREFIX + "resource-calculator.class";
    /** Class that calculates containers current resource utilization.*/
    public static final String NM_CONTAINER_MON_RESOURCE_CALCULATOR = NM_PREFIX
            + "container-monitor.resource-calculator.class";
    /** Class that calculates process tree resource utilization.*/
    public static final String NM_CONTAINER_MON_PROCESS_TREE = NM_PREFIX + "container-monitor.process-tree.class";
    public static final String PROCFS_USE_SMAPS_BASED_RSS_ENABLED = NM_PREFIX
            + "container-monitor.procfs-tree.smaps-based-rss.enabled";
    public static final boolean DEFAULT_PROCFS_USE_SMAPS_BASED_RSS_ENABLED = false;

    /** Enable/disable container metrics. */
    @Private
    public static final String NM_CONTAINER_METRICS_ENABLE = NM_PREFIX + "container-metrics.enable";
    @Private
    public static final boolean DEFAULT_NM_CONTAINER_METRICS_ENABLE = true;

    /** Container metrics flush period. -1 for flush on completion. */
    @Private
    public static final String NM_CONTAINER_METRICS_PERIOD_MS = NM_PREFIX + "container-metrics.period-ms";
    @Private
    public static final int DEFAULT_NM_CONTAINER_METRICS_PERIOD_MS = -1;

    /** The delay time ms to unregister container metrics after completion. */
    @Private
    public static final String NM_CONTAINER_METRICS_UNREGISTER_DELAY_MS = NM_PREFIX
            + "container-metrics.unregister-delay-ms";
    @Private
    public static final int DEFAULT_NM_CONTAINER_METRICS_UNREGISTER_DELAY_MS = 10000;

    /** Prefix for all node manager disk health checker configs. */
    private static final String NM_DISK_HEALTH_CHECK_PREFIX = "yarn.nodemanager.disk-health-checker.";
    /**
     * Enable/Disable disks' health checker. Default is true. An expert level
     * configuration property.
     */
    public static final String NM_DISK_HEALTH_CHECK_ENABLE = NM_DISK_HEALTH_CHECK_PREFIX + "enable";
    /** Frequency of running disks' health checker. */
    public static final String NM_DISK_HEALTH_CHECK_INTERVAL_MS = NM_DISK_HEALTH_CHECK_PREFIX + "interval-ms";
    /** By default, disks' health is checked every 2 minutes. */
    public static final long DEFAULT_NM_DISK_HEALTH_CHECK_INTERVAL_MS = 2 * 60 * 1000;

    /**
     * The minimum fraction of number of disks to be healthy for the nodemanager
     * to launch new containers. This applies to nm-local-dirs and nm-log-dirs.
     */
    public static final String NM_MIN_HEALTHY_DISKS_FRACTION = NM_DISK_HEALTH_CHECK_PREFIX + "min-healthy-disks";
    /**
     * By default, at least 25% of disks are to be healthy to say that the node is
     * healthy in terms of disks.
     */
    public static final float DEFAULT_NM_MIN_HEALTHY_DISKS_FRACTION = 0.25F;

    /**
     * The maximum percentage of disk space that can be used after which a disk is
     * marked as offline. Values can range from 0.0 to 100.0. If the value is
     * greater than or equal to 100, NM will check for full disk. This applies to
     * nm-local-dirs and nm-log-dirs.
     */
    public static final String NM_MAX_PER_DISK_UTILIZATION_PERCENTAGE = NM_DISK_HEALTH_CHECK_PREFIX
            + "max-disk-utilization-per-disk-percentage";
    /**
     * By default, 90% of the disk can be used before it is marked as offline.
     */
    public static final float DEFAULT_NM_MAX_PER_DISK_UTILIZATION_PERCENTAGE = 90.0F;

    /**
     * The low threshold percentage of disk space used when an offline disk is
     * marked as online. Values can range from 0.0 to 100.0. The value shouldn't
     * be more than NM_MAX_PER_DISK_UTILIZATION_PERCENTAGE. If its value is
     * more than NM_MAX_PER_DISK_UTILIZATION_PERCENTAGE or not set, it will be
     * set to the same value as NM_MAX_PER_DISK_UTILIZATION_PERCENTAGE.
     * This applies to nm-local-dirs and nm-log-dirs.
     */
    public static final String NM_WM_LOW_PER_DISK_UTILIZATION_PERCENTAGE = NM_DISK_HEALTH_CHECK_PREFIX
            + "disk-utilization-watermark-low-per-disk-percentage";

    /**
     * The minimum space that must be available on a local dir for it to be used.
     * This applies to nm-local-dirs and nm-log-dirs.
     */
    public static final String NM_MIN_PER_DISK_FREE_SPACE_MB = NM_DISK_HEALTH_CHECK_PREFIX
            + "min-free-space-per-disk-mb";
    /**
     * By default, all of the disk can be used before it is marked as offline.
     */
    public static final long DEFAULT_NM_MIN_PER_DISK_FREE_SPACE_MB = 0;

    /** Frequency of running node health script.*/
    public static final String NM_HEALTH_CHECK_INTERVAL_MS = NM_PREFIX + "health-checker.interval-ms";
    public static final long DEFAULT_NM_HEALTH_CHECK_INTERVAL_MS = 10 * 60 * 1000;

    /** Health check script time out period.*/
    public static final String NM_HEALTH_CHECK_SCRIPT_TIMEOUT_MS = NM_PREFIX + "health-checker.script.timeout-ms";
    public static final long DEFAULT_NM_HEALTH_CHECK_SCRIPT_TIMEOUT_MS = 2 * DEFAULT_NM_HEALTH_CHECK_INTERVAL_MS;

    /** The health check script to run.*/
    public static final String NM_HEALTH_CHECK_SCRIPT_PATH = NM_PREFIX + "health-checker.script.path";

    /** The arguments to pass to the health check script.*/
    public static final String NM_HEALTH_CHECK_SCRIPT_OPTS = NM_PREFIX + "health-checker.script.opts";

    /** The JVM options used on forking ContainerLocalizer process
        by container executor. */
    public static final String NM_CONTAINER_LOCALIZER_JAVA_OPTS_KEY = NM_PREFIX + "container-localizer.java.opts";
    public static final String NM_CONTAINER_LOCALIZER_JAVA_OPTS_DEFAULT = "-Xmx256m";

    /** The log level of container localizer process. */
    public static final String NM_CONTAINER_LOCALIZER_LOG_LEVEL = NM_PREFIX + "container-localizer.log.level";
    public static final String NM_CONTAINER_LOCALIZER_LOG_LEVEL_DEFAULT = "INFO";

    /** Prefix for runtime configuration constants. */
    public static final String LINUX_CONTAINER_RUNTIME_PREFIX = NM_PREFIX + "runtime.linux.";

    /**
     * Comma separated list of runtimes that are allowed when using
     * LinuxContainerExecutor. The standard values are:
     * <ul>
     *   <li>default</li>
     *   <li>docker</li>
     *   <li>javasandbox</li>
     * </ul>
     */
    public static final String LINUX_CONTAINER_RUNTIME_ALLOWED_RUNTIMES = LINUX_CONTAINER_RUNTIME_PREFIX
            + "allowed-runtimes";

    public static final String LINUX_CONTAINER_RUNTIME_CLASS_FMT = LINUX_CONTAINER_RUNTIME_PREFIX + "%s.class";

    /** The default list of allowed runtimes when using LinuxContainerExecutor. */
    public static final String[] DEFAULT_LINUX_CONTAINER_RUNTIME_ALLOWED_RUNTIMES = { "default" };

    /** Default runtime to be used. */
    public static final String LINUX_CONTAINER_RUNTIME_TYPE = LINUX_CONTAINER_RUNTIME_PREFIX + "type";

    public static final String DOCKER_CONTAINER_RUNTIME_PREFIX = LINUX_CONTAINER_RUNTIME_PREFIX + "docker.";

    /** Default docker image to be used. */
    public static final String NM_DOCKER_IMAGE_NAME = DOCKER_CONTAINER_RUNTIME_PREFIX + "image-name";

    /** Capabilities allowed (and added by default) for docker containers. **/
    public static final String NM_DOCKER_CONTAINER_CAPABILITIES = DOCKER_CONTAINER_RUNTIME_PREFIX + "capabilities";

    /** These are the default capabilities added by docker. We'll use the same
     * set here. While these may not be case-sensitive from a docker
     * perspective, it is best to keep these uppercase.
     */
    public static final String[] DEFAULT_NM_DOCKER_CONTAINER_CAPABILITIES = { "CHOWN", "DAC_OVERRIDE", "FSETID",
            "FOWNER", "MKNOD", "NET_RAW", "SETGID", "SETUID", "SETFCAP", "SETPCAP", "NET_BIND_SERVICE",
            "SYS_CHROOT", "KILL", "AUDIT_WRITE" };

    /** Allow privileged containers. Use with extreme care. */
    public static final String NM_DOCKER_ALLOW_PRIVILEGED_CONTAINERS = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "privileged-containers.allowed";

    /** Privileged containers are disabled by default. */
    public static final boolean DEFAULT_NM_DOCKER_ALLOW_PRIVILEGED_CONTAINERS = false;

    /** enable user remapping. */
    public static final String NM_DOCKER_ENABLE_USER_REMAPPING = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "enable-userremapping.allowed";

    /** Set enable user remapping as false by default. */
    public static final boolean DEFAULT_NM_DOCKER_ENABLE_USER_REMAPPING = true;

    /** lower limit for acceptable uids of user remapped user. */
    public static final String NM_DOCKER_USER_REMAPPING_UID_THRESHOLD = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "userremapping-uid-threshold";

    /** Set user remapping lower uid limit to 1 by default. */
    public static final int DEFAULT_NM_DOCKER_USER_REMAPPING_UID_THRESHOLD = 1;

    /** lower limit for acceptable gids of user remapped user. */
    public static final String NM_DOCKER_USER_REMAPPING_GID_THRESHOLD = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "userremapping-gid-threshold";

    /** Set user remapping lower gid limit to 1 by default. */
    public static final int DEFAULT_NM_DOCKER_USER_REMAPPING_GID_THRESHOLD = 1;

    /** ACL list for users allowed to run privileged containers. */
    public static final String NM_DOCKER_PRIVILEGED_CONTAINERS_ACL = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "privileged-containers.acl";

    /** Default list for users allowed to run privileged containers is empty. */
    public static final String DEFAULT_NM_DOCKER_PRIVILEGED_CONTAINERS_ACL = "";

    /** The set of networks allowed when launching containers using the
     * DockerContainerRuntime. */
    public static final String NM_DOCKER_ALLOWED_CONTAINER_NETWORKS = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "allowed-container-networks";

    /** The set of networks allowed when launching containers using the
     * DockerContainerRuntime. */
    public static final String[] DEFAULT_NM_DOCKER_ALLOWED_CONTAINER_NETWORKS = { "host", "none", "bridge" };

    /** The network used when launching containers using the
     * DockerContainerRuntime when no network is specified in the request. This
     *  network must be one of the (configurable) set of allowed container
     *  networks. */
    public static final String NM_DOCKER_DEFAULT_CONTAINER_NETWORK = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "default-container-network";

    /** The network used when launching containers using the
     * DockerContainerRuntime when no network is specified in the request and
     * no default network is configured.
     * . */
    public static final String DEFAULT_NM_DOCKER_DEFAULT_CONTAINER_NETWORK = "host";

    /** Allow host pid namespace for containers. Use with care. */
    public static final String NM_DOCKER_ALLOW_HOST_PID_NAMESPACE = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "host-pid-namespace.allowed";

    /** Host pid namespace for containers is disabled by default. */
    public static final boolean DEFAULT_NM_DOCKER_ALLOW_HOST_PID_NAMESPACE = false;

    /**
     * Whether or not users are allowed to request that Docker containers honor
     * the debug deletion delay. This is useful for troubleshooting Docker
     * container related launch failures.
     */
    public static final String NM_DOCKER_ALLOW_DELAYED_REMOVAL = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "delayed-removal.allowed";

    /**
     * The default value on whether or not a user can request that Docker
     * containers honor the debug deletion delay.
     */
    public static final boolean DEFAULT_NM_DOCKER_ALLOW_DELAYED_REMOVAL = false;

    /**
     * A configurable value to pass to the Docker Stop command. This value
     * defines the number of seconds between the docker stop command sending
     * a SIGTERM and a SIGKILL.
     *
     * @deprecated use {@link YarnConfiguration#NM_SLEEP_DELAY_BEFORE_SIGKILL_MS}
     */
    @Deprecated
    public static final String NM_DOCKER_STOP_GRACE_PERIOD = DOCKER_CONTAINER_RUNTIME_PREFIX + "stop.grace-period";

    /**
     * The default value for the grace period between the SIGTERM and the
     * SIGKILL in the Docker Stop command.
     */
    @Deprecated
    public static final int DEFAULT_NM_DOCKER_STOP_GRACE_PERIOD = 10;

    /** The default list of read-only mounts to be bind-mounted into all
     *  Docker containers that use DockerContainerRuntime. */
    public static final String NM_DOCKER_DEFAULT_RO_MOUNTS = DOCKER_CONTAINER_RUNTIME_PREFIX + "default-ro-mounts";

    /** The default list of read-write mounts to be bind-mounted into all
     *  Docker containers that use DockerContainerRuntime. */
    public static final String NM_DOCKER_DEFAULT_RW_MOUNTS = DOCKER_CONTAINER_RUNTIME_PREFIX + "default-rw-mounts";

    /** The default list of tmpfs mounts to be mounted into all
     *  Docker containers that use DockerContainerRuntime. */
    public static final String NM_DOCKER_DEFAULT_TMPFS_MOUNTS = DOCKER_CONTAINER_RUNTIME_PREFIX
            + "default-tmpfs-mounts";

    /** The mode in which the Java Container Sandbox should run detailed by
     *  the JavaSandboxLinuxContainerRuntime. */
    public static final String YARN_CONTAINER_SANDBOX = LINUX_CONTAINER_RUNTIME_PREFIX + "sandbox-mode";
    public static final String DEFAULT_YARN_CONTAINER_SANDBOX = "disabled";

    /** Permissions for application local directories.*/
    public static final String YARN_CONTAINER_SANDBOX_FILE_PERMISSIONS = YARN_CONTAINER_SANDBOX
            + ".local-dirs.permissions";
    public static final String DEFAULT_YARN_CONTAINER_SANDBOX_FILE_PERMISSIONS = "read";

    /** Location for non-default java policy file.*/
    public static final String YARN_CONTAINER_SANDBOX_POLICY = YARN_CONTAINER_SANDBOX + ".policy";

    /** Prefix for group to policy file mapping.*/
    public static final String YARN_CONTAINER_SANDBOX_POLICY_GROUP_PREFIX = YARN_CONTAINER_SANDBOX_POLICY
            + ".group.";

    /** The group which will run by default without the java security manager.*/
    public static final String YARN_CONTAINER_SANDBOX_WHITELIST_GROUP = YARN_CONTAINER_SANDBOX + ".whitelist-group";

    /** The path to the Linux container executor.*/
    public static final String NM_LINUX_CONTAINER_EXECUTOR_PATH = NM_PREFIX + "linux-container-executor.path";

    /**
     * True if linux-container-executor should limit itself to one user
     * when running in non-secure mode.
     */
    public static final String NM_NONSECURE_MODE_LIMIT_USERS = NM_PREFIX
            + "linux-container-executor.nonsecure-mode.limit-users";

    public static final boolean DEFAULT_NM_NONSECURE_MODE_LIMIT_USERS = true;

    /**
     * The UNIX user that containers will run as when Linux-container-executor
     * is used in nonsecure mode (a use case for this is using cgroups).
     */
    public static final String NM_NONSECURE_MODE_LOCAL_USER_KEY = NM_PREFIX
            + "linux-container-executor.nonsecure-mode.local-user";

    public static final String DEFAULT_NM_NONSECURE_MODE_LOCAL_USER = "nobody";

    /**
     * The allowed pattern for UNIX user names enforced by 
     * Linux-container-executor when used in nonsecure mode (use case for this 
     * is using cgroups). The default value is taken from /usr/sbin/adduser
     */
    public static final String NM_NONSECURE_MODE_USER_PATTERN_KEY = NM_PREFIX
            + "linux-container-executor.nonsecure-mode.user-pattern";

    public static final String DEFAULT_NM_NONSECURE_MODE_USER_PATTERN = "^[_.A-Za-z0-9][-@_.A-Za-z0-9]{0,255}?[$]?$";

    /** The type of resource enforcement to use with the
     *  linux container executor.
     */
    public static final String NM_LINUX_CONTAINER_RESOURCES_HANDLER = NM_PREFIX
            + "linux-container-executor.resources-handler.class";

    /** The path the linux container executor should use for cgroups */
    public static final String NM_LINUX_CONTAINER_CGROUPS_HIERARCHY = NM_PREFIX
            + "linux-container-executor.cgroups.hierarchy";

    /** Whether the linux container executor should mount cgroups if not found */
    public static final String NM_LINUX_CONTAINER_CGROUPS_MOUNT = NM_PREFIX
            + "linux-container-executor.cgroups.mount";

    /** Where the linux container executor should mount cgroups if not found */
    public static final String NM_LINUX_CONTAINER_CGROUPS_MOUNT_PATH = NM_PREFIX
            + "linux-container-executor.cgroups.mount-path";

    /**
     * Whether the apps should run in strict resource usage mode(not allowed to
     * use spare CPU)
     */
    public static final String NM_LINUX_CONTAINER_CGROUPS_STRICT_RESOURCE_USAGE = NM_PREFIX
            + "linux-container-executor.cgroups.strict-resource-usage";
    public static final boolean DEFAULT_NM_LINUX_CONTAINER_CGROUPS_STRICT_RESOURCE_USAGE = false;

    // Configurations for applicaiton life time monitor feature
    public static final String RM_APPLICATION_MONITOR_INTERVAL_MS = RM_PREFIX
            + "application-timeouts.monitor.interval-ms";

    public static final long DEFAULT_RM_APPLICATION_MONITOR_INTERVAL_MS = 3000;

    /**
     * Interval of time the linux container executor should try cleaning up
     * cgroups entry when cleaning up a container. This is required due to what 
     * it seems a race condition because the SIGTERM/SIGKILL is asynch.
     */
    public static final String NM_LINUX_CONTAINER_CGROUPS_DELETE_TIMEOUT = NM_PREFIX
            + "linux-container-executor.cgroups.delete-timeout-ms";

    public static final long DEFAULT_NM_LINUX_CONTAINER_CGROUPS_DELETE_TIMEOUT = 1000;

    /**
     * Delay between attempts to remove linux cgroup.
     */
    public static final String NM_LINUX_CONTAINER_CGROUPS_DELETE_DELAY = NM_PREFIX
            + "linux-container-executor.cgroups.delete-delay-ms";

    public static final long DEFAULT_NM_LINUX_CONTAINER_CGROUPS_DELETE_DELAY = 20;

    /**
     * Indicates if memory and CPU limits will be set for the Windows Job
     * Object for the containers launched by the default container executor.
     */
    public static final String NM_WINDOWS_CONTAINER_MEMORY_LIMIT_ENABLED = NM_PREFIX
            + "windows-container.memory-limit.enabled";
    public static final boolean DEFAULT_NM_WINDOWS_CONTAINER_MEMORY_LIMIT_ENABLED = false;

    public static final String NM_WINDOWS_CONTAINER_CPU_LIMIT_ENABLED = NM_PREFIX
            + "windows-container.cpu-limit.enabled";
    public static final boolean DEFAULT_NM_WINDOWS_CONTAINER_CPU_LIMIT_ENABLED = false;

    /** 
    /* The Windows group that the windows-secure-container-executor should run as.
    */
    public static final String NM_WINDOWS_SECURE_CONTAINER_GROUP = NM_PREFIX
            + "windows-secure-container-executor.group";

    /** T-file compression types used to compress aggregated logs.*/
    public static final String NM_LOG_AGG_COMPRESSION_TYPE = NM_PREFIX + "log-aggregation.compression-type";
    public static final String DEFAULT_NM_LOG_AGG_COMPRESSION_TYPE = "none";

    /** The kerberos principal for the node manager.*/
    public static final String NM_PRINCIPAL = NM_PREFIX + "principal";

    public static final String NM_AUX_SERVICES = NM_PREFIX + "aux-services";

    public static final String NM_AUX_SERVICE_FMT = NM_PREFIX + "aux-services.%s.class";

    public static final String NM_AUX_SERVICES_CLASSPATH = NM_AUX_SERVICES + ".%s.classpath";

    public static final String NM_AUX_SERVICE_REMOTE_CLASSPATH = NM_AUX_SERVICES + ".%s.remote-classpath";

    public static final String NM_AUX_SERVICES_SYSTEM_CLASSES = NM_AUX_SERVICES + ".%s.system-classes";

    public static final String NM_USER_HOME_DIR = NM_PREFIX + "user-home-dir";

    public static final String NM_CONTAINER_STDERR_PATTERN = NM_PREFIX + "container.stderr.pattern";

    public static final String DEFAULT_NM_CONTAINER_STDERR_PATTERN = "{*stderr*,*STDERR*}";

    public static final String NM_CONTAINER_STDERR_BYTES = NM_PREFIX + "container.stderr.tail.bytes";

    public static final long DEFAULT_NM_CONTAINER_STDERR_BYTES = 4 * 1024;

    /**The kerberos principal to be used for spnego filter for NM.*/
    public static final String NM_WEBAPP_SPNEGO_USER_NAME_KEY = NM_PREFIX + "webapp.spnego-principal";

    /**The kerberos keytab to be used for spnego filter for NM.*/
    public static final String NM_WEBAPP_SPNEGO_KEYTAB_FILE_KEY = NM_PREFIX + "webapp.spnego-keytab-file";

    public static final String DEFAULT_NM_USER_HOME_DIR = "/home/";

    public static final String NM_RECOVERY_PREFIX = NM_PREFIX + "recovery.";
    public static final String NM_RECOVERY_ENABLED = NM_RECOVERY_PREFIX + "enabled";
    public static final boolean DEFAULT_NM_RECOVERY_ENABLED = false;

    public static final String NM_RECOVERY_DIR = NM_RECOVERY_PREFIX + "dir";

    /** The time in seconds between full compactions of the NM state database.
     *  Setting the interval to zero disables the full compaction cycles.
     */
    public static final String NM_RECOVERY_COMPACTION_INTERVAL_SECS = NM_RECOVERY_PREFIX
            + "compaction-interval-secs";
    public static final int DEFAULT_NM_RECOVERY_COMPACTION_INTERVAL_SECS = 3600;

    public static final String NM_RECOVERY_SUPERVISED = NM_RECOVERY_PREFIX + "supervised";
    public static final boolean DEFAULT_NM_RECOVERY_SUPERVISED = false;

    public static final String NM_LOG_AGG_POLICY_CLASS = NM_PREFIX + "log-aggregation.policy.class";

    public static final String NM_LOG_AGG_POLICY_CLASS_PARAMETERS = NM_PREFIX + "log-aggregation.policy.parameters";

    ////////////////////////////////
    // Web Proxy Configs
    ////////////////////////////////
    public static final String PROXY_PREFIX = "yarn.web-proxy.";

    /** The kerberos principal for the proxy.*/
    public static final String PROXY_PRINCIPAL = PROXY_PREFIX + "principal";

    /** Keytab for Proxy.*/
    public static final String PROXY_KEYTAB = PROXY_PREFIX + "keytab";

    /** The address for the web proxy.*/
    public static final String PROXY_ADDRESS = PROXY_PREFIX + "address";
    public static final int DEFAULT_PROXY_PORT = 9099;
    public static final String DEFAULT_PROXY_ADDRESS = "0.0.0.0:" + DEFAULT_PROXY_PORT;

    /**
     * YARN Service Level Authorization
     */
    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_RESOURCETRACKER_PROTOCOL = "security.resourcetracker.protocol.acl";
    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_APPLICATIONCLIENT_PROTOCOL = "security.applicationclient.protocol.acl";
    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_RESOURCEMANAGER_ADMINISTRATION_PROTOCOL = "security.resourcemanager-administration.protocol.acl";
    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_APPLICATIONMASTER_PROTOCOL = "security.applicationmaster.protocol.acl";
    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_DISTRIBUTEDSCHEDULING_PROTOCOL = "security.distributedscheduling.protocol.acl";

    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_CONTAINER_MANAGEMENT_PROTOCOL = "security.containermanagement.protocol.acl";
    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_RESOURCE_LOCALIZER = "security.resourcelocalizer.protocol.acl";

    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_APPLICATIONHISTORY_PROTOCOL = "security.applicationhistory.protocol.acl";

    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_COLLECTOR_NODEMANAGER_PROTOCOL = "security.collector-nodemanager.protocol.acl";

    public static final String YARN_SECURITY_SERVICE_AUTHORIZATION_APPLICATIONMASTER_NODEMANAGER_PROTOCOL = "security.applicationmaster-nodemanager.applicationmaster.protocol.acl";

    /** No. of milliseconds to wait between sending a SIGTERM and SIGKILL
     * to a running container */
    public static final String NM_SLEEP_DELAY_BEFORE_SIGKILL_MS = NM_PREFIX + "sleep-delay-before-sigkill.ms";
    public static final long DEFAULT_NM_SLEEP_DELAY_BEFORE_SIGKILL_MS = 250;

    /** Max time to wait for a process to come up when trying to cleanup
     * container resources */
    public static final String NM_PROCESS_KILL_WAIT_MS = NM_PREFIX + "process-kill-wait.ms";
    public static final long DEFAULT_NM_PROCESS_KILL_WAIT_MS = 5000;

    /** Max time to wait to establish a connection to RM */
    public static final String RESOURCEMANAGER_CONNECT_MAX_WAIT_MS = RM_PREFIX + "connect.max-wait.ms";
    public static final long DEFAULT_RESOURCEMANAGER_CONNECT_MAX_WAIT_MS = 15 * 60 * 1000;

    /** Time interval between each attempt to connect to RM */
    public static final String RESOURCEMANAGER_CONNECT_RETRY_INTERVAL_MS = RM_PREFIX + "connect.retry-interval.ms";
    public static final long DEFAULT_RESOURCEMANAGER_CONNECT_RETRY_INTERVAL_MS = 30 * 1000;

    public static final String DISPATCHER_DRAIN_EVENTS_TIMEOUT = YARN_PREFIX + "dispatcher.drain-events.timeout";

    public static final long DEFAULT_DISPATCHER_DRAIN_EVENTS_TIMEOUT = 300000;

    /**
     * CLASSPATH for YARN applications. A comma-separated list of CLASSPATH
     * entries
     */
    public static final String YARN_APPLICATION_CLASSPATH = YARN_PREFIX + "application.classpath";

    /** The setting that controls whether AMRMProxy is enabled or not. */
    public static final String AMRM_PROXY_ENABLED = NM_PREFIX + "amrmproxy.enabled";
    public static final boolean DEFAULT_AMRM_PROXY_ENABLED = false;

    public static final String AMRM_PROXY_ADDRESS = NM_PREFIX + "amrmproxy.address";
    public static final int DEFAULT_AMRM_PROXY_PORT = 8049;
    public static final String DEFAULT_AMRM_PROXY_ADDRESS = "0.0.0.0:" + DEFAULT_AMRM_PROXY_PORT;

    public static final String AMRM_PROXY_CLIENT_THREAD_COUNT = NM_PREFIX + "amrmproxy.client.thread-count";
    public static final int DEFAULT_AMRM_PROXY_CLIENT_THREAD_COUNT = 3;

    public static final String AMRM_PROXY_INTERCEPTOR_CLASS_PIPELINE = NM_PREFIX
            + "amrmproxy.interceptor-class.pipeline";
    public static final String DEFAULT_AMRM_PROXY_INTERCEPTOR_CLASS_PIPELINE = "org.apache.hadoop.yarn.server.nodemanager.amrmproxy."
            + "DefaultRequestInterceptor";
    public static final String AMRM_PROXY_HA_ENABLED = NM_PREFIX + "amrmproxy.ha.enable";
    public static final boolean DEFAULT_AMRM_PROXY_HA_ENABLED = false;

    /**
     * Default platform-agnostic CLASSPATH for YARN applications. A
     * comma-separated list of CLASSPATH entries. The parameter expansion marker
     * will be replaced with real parameter expansion marker ('%' for Windows and
     * '$' for Linux) by NodeManager on container launch. For example: {{VAR}}
     * will be replaced as $VAR on Linux, and %VAR% on Windows.
     */
    @Public
    @Unstable
    public static final String[] DEFAULT_YARN_CROSS_PLATFORM_APPLICATION_CLASSPATH = {
            ApplicationConstants.Environment.HADOOP_CONF_DIR.$$(),
            ApplicationConstants.Environment.HADOOP_COMMON_HOME.$$() + "/share/hadoop/common/*",
            ApplicationConstants.Environment.HADOOP_COMMON_HOME.$$() + "/share/hadoop/common/lib/*",
            ApplicationConstants.Environment.HADOOP_HDFS_HOME.$$() + "/share/hadoop/hdfs/*",
            ApplicationConstants.Environment.HADOOP_HDFS_HOME.$$() + "/share/hadoop/hdfs/lib/*",
            ApplicationConstants.Environment.HADOOP_YARN_HOME.$$() + "/share/hadoop/yarn/*",
            ApplicationConstants.Environment.HADOOP_YARN_HOME.$$() + "/share/hadoop/yarn/lib/*" };
    /**
     * <p>
     * Default platform-specific CLASSPATH for YARN applications. A
     * comma-separated list of CLASSPATH entries constructed based on the client
     * OS environment expansion syntax.
     * </p>
     * <p>
     * Note: Use {@link #DEFAULT_YARN_CROSS_PLATFORM_APPLICATION_CLASSPATH} for
     * cross-platform practice i.e. submit an application from a Windows client to
     * a Linux/Unix server or vice versa.
     * </p>
     */
    public static final String[] DEFAULT_YARN_APPLICATION_CLASSPATH = {
            ApplicationConstants.Environment.HADOOP_CONF_DIR.$(),
            ApplicationConstants.Environment.HADOOP_COMMON_HOME.$() + "/share/hadoop/common/*",
            ApplicationConstants.Environment.HADOOP_COMMON_HOME.$() + "/share/hadoop/common/lib/*",
            ApplicationConstants.Environment.HADOOP_HDFS_HOME.$() + "/share/hadoop/hdfs/*",
            ApplicationConstants.Environment.HADOOP_HDFS_HOME.$() + "/share/hadoop/hdfs/lib/*",
            ApplicationConstants.Environment.HADOOP_YARN_HOME.$() + "/share/hadoop/yarn/*",
            ApplicationConstants.Environment.HADOOP_YARN_HOME.$() + "/share/hadoop/yarn/lib/*" };

    /** Container temp directory */
    public static final String DEFAULT_CONTAINER_TEMP_DIR = "./tmp";

    public static final String IS_MINI_YARN_CLUSTER = YARN_PREFIX + "is.minicluster";

    public static final String YARN_MC_PREFIX = YARN_PREFIX + "minicluster.";

    /** Whether to use fixed ports with the minicluster. */
    public static final String YARN_MINICLUSTER_FIXED_PORTS = YARN_MC_PREFIX + "fixed.ports";

    /**
     * Default is false to be able to run tests concurrently without port
     * conflicts.
     */
    public static final boolean DEFAULT_YARN_MINICLUSTER_FIXED_PORTS = false;

    /**
     * Whether the NM should use RPC to connect to the RM. Default is false.
     * Can be set to true only when using fixed ports.
     */
    public static final String YARN_MINICLUSTER_USE_RPC = YARN_MC_PREFIX + "use-rpc";
    public static final boolean DEFAULT_YARN_MINICLUSTER_USE_RPC = false;

    /**
     * Whether users are explicitly trying to control resource monitoring
     * configuration for the MiniYARNCluster. Disabled by default.
     */
    public static final String YARN_MINICLUSTER_CONTROL_RESOURCE_MONITORING = YARN_MC_PREFIX
            + "control-resource-monitoring";
    public static final boolean DEFAULT_YARN_MINICLUSTER_CONTROL_RESOURCE_MONITORING = false;

    /** Allow changing the memory for the NodeManager in the MiniYARNCluster */
    public static final String YARN_MINICLUSTER_NM_PMEM_MB = YARN_MC_PREFIX + YarnConfiguration.NM_PMEM_MB;
    public static final int DEFAULT_YARN_MINICLUSTER_NM_PMEM_MB = 4 * 1024;

    /** The log directory for the containers */
    public static final String YARN_APP_CONTAINER_LOG_DIR = YARN_PREFIX + "app.container.log.dir";

    public static final String YARN_APP_CONTAINER_LOG_SIZE = YARN_PREFIX + "app.container.log.filesize";

    public static final String YARN_APP_CONTAINER_LOG_BACKUPS = YARN_PREFIX + "app.container.log.backups";

    ////////////////////////////////
    // Timeline Service Configs
    ////////////////////////////////

    public static final String TIMELINE_SERVICE_PREFIX = YARN_PREFIX + "timeline-service.";

    public static final String TIMELINE_SERVICE_VERSION = TIMELINE_SERVICE_PREFIX + "version";
    public static final float DEFAULT_TIMELINE_SERVICE_VERSION = 1.0f;

    public static final String TIMELINE_SERVICE_VERSIONS = TIMELINE_SERVICE_PREFIX + "versions";

    /**
     * Comma separated list of names for UIs hosted in the timeline server
     * (For pluggable UIs).
     */
    public static final String TIMELINE_SERVICE_UI_NAMES = TIMELINE_SERVICE_PREFIX + "ui-names";

    /** Relative web path that will serve up this UI (For pluggable UIs). */
    public static final String TIMELINE_SERVICE_UI_WEB_PATH_PREFIX = TIMELINE_SERVICE_PREFIX + "ui-web-path.";

    /** Timeline client settings. */
    public static final String TIMELINE_SERVICE_CLIENT_PREFIX = TIMELINE_SERVICE_PREFIX + "client.";

    /**
     * Path to war file or static content directory for this UI
     * (For pluggable UIs).
     */
    public static final String TIMELINE_SERVICE_UI_ON_DISK_PATH_PREFIX = TIMELINE_SERVICE_PREFIX
            + "ui-on-disk-path.";

    /**
     * The setting for timeline service v1.5
     */
    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX = TIMELINE_SERVICE_PREFIX
            + "entity-group-fs-store.";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_CACHE_STORE = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "cache-store-class";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_ACTIVE_DIR = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "active-dir";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_ACTIVE_DIR_DEFAULT = "/tmp/entity-file-history/active";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_DONE_DIR = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "done-dir";
    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_DONE_DIR_DEFAULT = "/tmp/entity-file-history/done";

    public static final String TIMELINE_SERVICE_ENTITY_GROUP_PLUGIN_CLASSES = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "group-id-plugin-classes";

    public static final String TIMELINE_SERVICE_ENTITY_GROUP_PLUGIN_CLASSPATH = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "group-id-plugin-classpath";

    public static final String TIMELINE_SERVICE_ENTITY_GROUP_PLUGIN_SYSTEM_CLASSES = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "group-id-plugin-system-classes";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_SUMMARY_STORE = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "summary-store";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_SUMMARY_ENTITY_TYPES = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "summary-entity-types";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_SCAN_INTERVAL_SECONDS = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "scan-interval-seconds";
    public static final long TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_SCAN_INTERVAL_SECONDS_DEFAULT = 60;

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_THREADS = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "threads";
    public static final int TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_THREADS_DEFAULT = 16;

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_APP_CACHE_SIZE = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "app-cache-size";
    public static final int TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_APP_CACHE_SIZE_DEFAULT = 10;

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_CLEANER_INTERVAL_SECONDS = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "cleaner-interval-seconds";
    public static final int TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_CLEANER_INTERVAL_SECONDS_DEFAULT = 60 * 60;

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_RETAIN_SECONDS = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "retain-seconds";
    public static final int TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_RETAIN_SECONDS_DEFAULT = 7 * 24 * 60 * 60;

    // how old the most recent log of an UNKNOWN app needs to be in the active
    // directory before we treat it as COMPLETED
    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_UNKNOWN_ACTIVE_SECONDS = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "unknown-active-seconds";
    public static final int TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_UNKNOWN_ACTIVE_SECONDS_DEFAULT = 24 * 60 * 60;

    public static final String TIMELINE_SERVICE_LEVELDB_CACHE_READ_CACHE_SIZE = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "leveldb-cache-read-cache-size";

    public static final long DEFAULT_TIMELINE_SERVICE_LEVELDB_CACHE_READ_CACHE_SIZE = 10 * 1024 * 1024;

    public static final String TIMELINE_SERVICE_CLIENT_FD_FLUSH_INTERVAL_SECS = TIMELINE_SERVICE_CLIENT_PREFIX
            + "fd-flush-interval-secs";
    public static final long TIMELINE_SERVICE_CLIENT_FD_FLUSH_INTERVAL_SECS_DEFAULT = 10;

    public static final String TIMELINE_SERVICE_CLIENT_FD_CLEAN_INTERVAL_SECS = TIMELINE_SERVICE_CLIENT_PREFIX
            + "fd-clean-interval-secs";
    public static final long TIMELINE_SERVICE_CLIENT_FD_CLEAN_INTERVAL_SECS_DEFAULT = 60;

    public static final String TIMELINE_SERVICE_CLIENT_FD_RETAIN_SECS = TIMELINE_SERVICE_CLIENT_PREFIX
            + "fd-retain-secs";
    public static final long TIMELINE_SERVICE_CLIENT_FD_RETAIN_SECS_DEFAULT = 5 * 60;

    public static final String TIMELINE_SERVICE_CLIENT_INTERNAL_TIMERS_TTL_SECS = TIMELINE_SERVICE_CLIENT_PREFIX
            + "internal-timers-ttl-secs";
    public static final long TIMELINE_SERVICE_CLIENT_INTERNAL_TIMERS_TTL_SECS_DEFAULT = 7 * 60;

    public static final String TIMELINE_SERVICE_CLIENT_INTERNAL_ATTEMPT_DIR_CACHE_SIZE = TIMELINE_SERVICE_CLIENT_PREFIX
            + "internal-attempt-dir-cache-size";
    public static final int DEFAULT_TIMELINE_SERVICE_CLIENT_INTERNAL_ATTEMPT_DIR_CACHE_SIZE = 1000;

    // This is temporary solution. The configuration will be deleted once we have
    // the FileSystem API to check whether append operation is supported or not.
    public static final String TIMELINE_SERVICE_ENTITYFILE_FS_SUPPORT_APPEND = TIMELINE_SERVICE_PREFIX
            + "entity-file.fs-support-append";

    public static final String TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_WITH_USER_DIR = TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
            + "with-user-dir";

    /**
     * Settings for timeline service v2.0.
     */
    public static final String TIMELINE_SERVICE_READER_PREFIX = TIMELINE_SERVICE_PREFIX + "reader.";

    public static final String TIMELINE_SERVICE_WRITER_CLASS = TIMELINE_SERVICE_PREFIX + "writer.class";

    public static final String DEFAULT_TIMELINE_SERVICE_WRITER_CLASS = "org.apache.hadoop.yarn.server.timelineservice"
            + ".storage.HBaseTimelineWriterImpl";

    public static final String TIMELINE_SERVICE_READER_CLASS = TIMELINE_SERVICE_READER_PREFIX + "class";

    public static final String DEFAULT_TIMELINE_SERVICE_READER_CLASS = "org.apache.hadoop.yarn.server.timelineservice.storage"
            + ".HBaseTimelineReaderImpl";

    /**
     * default schema prefix for hbase tables.
     */
    public static final String DEFAULT_TIMELINE_SERVICE_HBASE_SCHEMA_PREFIX = "prod.";

    /**
     * config param name to override schema prefix.
     */
    public static final String TIMELINE_SERVICE_HBASE_SCHEMA_PREFIX_NAME = TIMELINE_SERVICE_PREFIX
            + "hbase-schema.prefix";

    /** The setting that controls how often the timeline collector flushes the
     * timeline writer.
     */
    public static final String TIMELINE_SERVICE_WRITER_FLUSH_INTERVAL_SECONDS = TIMELINE_SERVICE_PREFIX
            + "writer.flush-interval-seconds";

    public static final int DEFAULT_TIMELINE_SERVICE_WRITER_FLUSH_INTERVAL_SECONDS = 60;

    /**
     * The name for setting that controls how long the final value of
     * a metric of a completed app is retained before merging
     * into the flow sum.
     */
    public static final String APP_FINAL_VALUE_RETENTION_THRESHOLD = TIMELINE_SERVICE_PREFIX
            + "hbase.coprocessor.app-final-value-retention-milliseconds";

    /**
     * The name of the setting for the location of the coprocessor
     * jar on hdfs.
     */
    public static final String FLOW_RUN_COPROCESSOR_JAR_HDFS_LOCATION = TIMELINE_SERVICE_PREFIX
            + "hbase.coprocessor.jar.hdfs.location";

    /** default hdfs location for flowrun coprocessor jar. */
    public static final String DEFAULT_HDFS_LOCATION_FLOW_RUN_COPROCESSOR_JAR = "/hbase/coprocessor/hadoop-yarn-server-timelineservice.jar";

    /**
    * The name for setting that points to an optional HBase configuration
    * (hbase-site.xml file) with settings that will override the ones found on
    * the classpath.
    */
    public static final String TIMELINE_SERVICE_HBASE_CONFIGURATION_FILE = TIMELINE_SERVICE_PREFIX
            + "hbase.configuration.file";

    /**
     * The name for setting that enables or disables authentication checks
     * for reading timeline service v2 data.
     */
    public static final String TIMELINE_SERVICE_READ_AUTH_ENABLED = TIMELINE_SERVICE_PREFIX
            + "read.authentication.enabled";

    /**
     * The name for setting that controls how often in-memory app level
     * aggregation is kicked off in timeline collector.
     */
    public static final String TIMELINE_SERVICE_AGGREGATION_INTERVAL_SECS = TIMELINE_SERVICE_PREFIX
            + "app-aggregation-interval-secs";

    public static final int DEFAULT_TIMELINE_SERVICE_AGGREGATION_INTERVAL_SECS = 15;
    /**
     * The default setting for authentication checks for reading timeline
     * service v2 data.
     */
    public static final Boolean DEFAULT_TIMELINE_SERVICE_READ_AUTH_ENABLED = false;

    /**
     * The name for setting that lists the users and groups who are allowed
     * to read timeline service v2 data. It is a comma separated list of
     * user, followed by space, then comma separated list of groups.
     * It will allow this list of users and groups to read the data
     * and reject everyone else.
     */
    public static final String TIMELINE_SERVICE_READ_ALLOWED_USERS = TIMELINE_SERVICE_PREFIX + "read.allowed.users";

    /**
     * The default value for list of the users who are allowed to read
     * timeline service v2 data.
     */
    public static final String DEFAULT_TIMELINE_SERVICE_READ_ALLOWED_USERS = "";

    /**
     * The setting that controls how long the final value of a metric of a
     * completed app is retained before merging into the flow sum. Up to this time
     * after an application is completed out-of-order values that arrive can be
     * recognized and discarded at the cost of increased storage.
     */
    public static final long DEFAULT_APP_FINAL_VALUE_RETENTION_THRESHOLD = 3 * 24 * 60 * 60 * 1000L;

    public static final String ATS_APP_COLLECTOR_LINGER_PERIOD_IN_MS = TIMELINE_SERVICE_PREFIX
            + "app-collector.linger-period.ms";

    public static final int DEFAULT_ATS_APP_COLLECTOR_LINGER_PERIOD_IN_MS = 60000;

    public static final String NUMBER_OF_ASYNC_ENTITIES_TO_MERGE = TIMELINE_SERVICE_PREFIX
            + "timeline-client.number-of-async-entities-to-merge";

    public static final int DEFAULT_NUMBER_OF_ASYNC_ENTITIES_TO_MERGE = 10;

    /** default version for any flow. */
    public static final String DEFAULT_FLOW_VERSION = "1";

    /**
     * The time period for which timeline v2 client will wait for draining
     * leftover entities after stop.
     */
    public static final String TIMELINE_V2_CLIENT_DRAIN_TIME_MILLIS = TIMELINE_SERVICE_CLIENT_PREFIX
            + "drain-entities.timeout.ms";
    public static final long DEFAULT_TIMELINE_V2_CLIENT_DRAIN_TIME_MILLIS = 2000L;

    // mark app-history related configs @Private as application history is going
    // to be integrated into the timeline service
    @Private
    public static final String APPLICATION_HISTORY_PREFIX = TIMELINE_SERVICE_PREFIX
            + "generic-application-history.";

    /**
     *  The setting that controls whether application history service is
     *  enabled or not.
     */
    @Private
    public static final String APPLICATION_HISTORY_ENABLED = APPLICATION_HISTORY_PREFIX + "enabled";
    @Private
    public static final boolean DEFAULT_APPLICATION_HISTORY_ENABLED = false;

    /** Application history store class */
    @Private
    public static final String APPLICATION_HISTORY_STORE = APPLICATION_HISTORY_PREFIX + "store-class";

    /** Save container meta-info in the application history store. */
    @Private
    public static final String APPLICATION_HISTORY_SAVE_NON_AM_CONTAINER_META_INFO = APPLICATION_HISTORY_PREFIX
            + "save-non-am-container-meta-info";
    @Private
    public static final boolean DEFAULT_APPLICATION_HISTORY_SAVE_NON_AM_CONTAINER_META_INFO = true;

    /** URI for FileSystemApplicationHistoryStore */
    @Private
    public static final String FS_APPLICATION_HISTORY_STORE_URI = APPLICATION_HISTORY_PREFIX
            + "fs-history-store.uri";

    /** T-file compression types used to compress history data.*/
    @Private
    public static final String FS_APPLICATION_HISTORY_STORE_COMPRESSION_TYPE = APPLICATION_HISTORY_PREFIX
            + "fs-history-store.compression-type";
    @Private
    public static final String DEFAULT_FS_APPLICATION_HISTORY_STORE_COMPRESSION_TYPE = "none";

    /** The setting that controls whether timeline service is enabled or not. */
    public static final String TIMELINE_SERVICE_ENABLED = TIMELINE_SERVICE_PREFIX + "enabled";
    public static final boolean DEFAULT_TIMELINE_SERVICE_ENABLED = false;

    /** host:port address for timeline service RPC APIs. */
    public static final String TIMELINE_SERVICE_ADDRESS = TIMELINE_SERVICE_PREFIX + "address";
    public static final int DEFAULT_TIMELINE_SERVICE_PORT = 10200;
    public static final String DEFAULT_TIMELINE_SERVICE_ADDRESS = "0.0.0.0:" + DEFAULT_TIMELINE_SERVICE_PORT;

    /** The listening endpoint for the timeline service application.*/
    public static final String TIMELINE_SERVICE_BIND_HOST = TIMELINE_SERVICE_PREFIX + "bind-host";
    public static final String DEFAULT_TIMELINE_SERVICE_BIND_HOST = "0.0.0.0";

    /** The number of threads to handle client RPC API requests. */
    public static final String TIMELINE_SERVICE_HANDLER_THREAD_COUNT = TIMELINE_SERVICE_PREFIX
            + "handler-thread-count";
    public static final int DEFAULT_TIMELINE_SERVICE_CLIENT_THREAD_COUNT = 10;

    /** The address of the timeline service web application.*/
    public static final String TIMELINE_SERVICE_WEBAPP_ADDRESS = TIMELINE_SERVICE_PREFIX + "webapp.address";

    public static final int DEFAULT_TIMELINE_SERVICE_WEBAPP_PORT = 8188;
    public static final String DEFAULT_TIMELINE_SERVICE_WEBAPP_ADDRESS = "0.0.0.0:"
            + DEFAULT_TIMELINE_SERVICE_WEBAPP_PORT;

    /** The https address of the timeline service web application.*/
    public static final String TIMELINE_SERVICE_WEBAPP_HTTPS_ADDRESS = TIMELINE_SERVICE_PREFIX
            + "webapp.https.address";

    public static final int DEFAULT_TIMELINE_SERVICE_WEBAPP_HTTPS_PORT = 8190;
    public static final String DEFAULT_TIMELINE_SERVICE_WEBAPP_HTTPS_ADDRESS = "0.0.0.0:"
            + DEFAULT_TIMELINE_SERVICE_WEBAPP_HTTPS_PORT;

    /**
     * Defines the max number of applications could be fetched using
     * REST API or application history protocol and shown in timeline
     * server web ui.
     */
    public static final String APPLICATION_HISTORY_MAX_APPS = APPLICATION_HISTORY_PREFIX + "max-applications";
    public static final long DEFAULT_APPLICATION_HISTORY_MAX_APPS = 10000;

    /** Timeline service store class. */
    public static final String TIMELINE_SERVICE_STORE = TIMELINE_SERVICE_PREFIX + "store-class";

    /** Timeline service enable data age off */
    public static final String TIMELINE_SERVICE_TTL_ENABLE = TIMELINE_SERVICE_PREFIX + "ttl-enable";

    /** Timeline service length of time to retain data */
    public static final String TIMELINE_SERVICE_TTL_MS = TIMELINE_SERVICE_PREFIX + "ttl-ms";

    public static final long DEFAULT_TIMELINE_SERVICE_TTL_MS = 1000 * 60 * 60 * 24 * 7;

    /** Timeline service rolling period. Valid values are daily, half_daily,
     * quarter_daily, and hourly. */
    public static final String TIMELINE_SERVICE_ROLLING_PERIOD = TIMELINE_SERVICE_PREFIX + "rolling-period";

    /** Roll a new database each hour. */
    public static final String DEFAULT_TIMELINE_SERVICE_ROLLING_PERIOD = "hourly";

    /** Implementation specific configuration prefix for Timeline Service
     * leveldb.
     */
    public static final String TIMELINE_SERVICE_LEVELDB_PREFIX = TIMELINE_SERVICE_PREFIX
            + "leveldb-timeline-store.";

    /** Timeline service leveldb path */
    public static final String TIMELINE_SERVICE_LEVELDB_PATH = TIMELINE_SERVICE_LEVELDB_PREFIX + "path";

    /** Timeline service leveldb read cache (uncompressed blocks). This is
     * per rolling instance so should be tuned if using rolling leveldb
     * timeline store */
    public static final String TIMELINE_SERVICE_LEVELDB_READ_CACHE_SIZE = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "read-cache-size";

    /** Default leveldb read cache size if no configuration is specified. */
    public static final long DEFAULT_TIMELINE_SERVICE_LEVELDB_READ_CACHE_SIZE = 100 * 1024 * 1024;

    /** Timeline service leveldb write buffer size. */
    public static final String TIMELINE_SERVICE_LEVELDB_WRITE_BUFFER_SIZE = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "write-buffer-size";

    /** Default leveldb write buffer size if no configuration is specified. This
     * is per rolling instance so should be tuned if using rolling leveldb
     * timeline store. */
    public static final int DEFAULT_TIMELINE_SERVICE_LEVELDB_WRITE_BUFFER_SIZE = 16 * 1024 * 1024;

    /** Timeline service leveldb write batch size. This value can be tuned down
     * to reduce lock time for ttl eviction. */
    public static final String TIMELINE_SERVICE_LEVELDB_WRITE_BATCH_SIZE = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "write-batch-size";

    /** Default leveldb write batch size is no configuration is specified */
    public static final int DEFAULT_TIMELINE_SERVICE_LEVELDB_WRITE_BATCH_SIZE = 10000;

    /** Timeline service leveldb start time read cache (number of entities) */
    public static final String TIMELINE_SERVICE_LEVELDB_START_TIME_READ_CACHE_SIZE = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "start-time-read-cache-size";

    public static final int DEFAULT_TIMELINE_SERVICE_LEVELDB_START_TIME_READ_CACHE_SIZE = 10000;

    /** Timeline service leveldb start time write cache (number of entities) */
    public static final String TIMELINE_SERVICE_LEVELDB_START_TIME_WRITE_CACHE_SIZE = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "start-time-write-cache-size";

    public static final int DEFAULT_TIMELINE_SERVICE_LEVELDB_START_TIME_WRITE_CACHE_SIZE = 10000;

    /** Timeline service leveldb interval to wait between deletion rounds */
    public static final String TIMELINE_SERVICE_LEVELDB_TTL_INTERVAL_MS = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "ttl-interval-ms";

    public static final long DEFAULT_TIMELINE_SERVICE_LEVELDB_TTL_INTERVAL_MS = 1000 * 60 * 5;

    /** Timeline service leveldb number of concurrent open files. Tuned this
     * configuration to stay within system limits. This is per rolling instance
     * so should be tuned if using rolling leveldb timeline store. */
    public static final String TIMELINE_SERVICE_LEVELDB_MAX_OPEN_FILES = TIMELINE_SERVICE_LEVELDB_PREFIX
            + "max-open-files";

    /** Default leveldb max open files if no configuration is specified. */
    public static final int DEFAULT_TIMELINE_SERVICE_LEVELDB_MAX_OPEN_FILES = 1000;

    /** The Kerberos principal for the timeline server.*/
    public static final String TIMELINE_SERVICE_PRINCIPAL = TIMELINE_SERVICE_PREFIX + "principal";

    /** The Kerberos keytab for the timeline server.*/
    public static final String TIMELINE_SERVICE_KEYTAB = TIMELINE_SERVICE_PREFIX + "keytab";

    /** Enables cross origin support for timeline server.*/
    public static final String TIMELINE_SERVICE_HTTP_CROSS_ORIGIN_ENABLED = TIMELINE_SERVICE_PREFIX
            + "http-cross-origin.enabled";

    /** Default value for cross origin support for timeline server.*/
    public static final boolean TIMELINE_SERVICE_HTTP_CROSS_ORIGIN_ENABLED_DEFAULT = false;

    /** Timeline client call, max retries (-1 means no limit) */
    public static final String TIMELINE_SERVICE_CLIENT_MAX_RETRIES = TIMELINE_SERVICE_CLIENT_PREFIX + "max-retries";

    public static final int DEFAULT_TIMELINE_SERVICE_CLIENT_MAX_RETRIES = 30;

    /** Timeline client call, retry interval */
    public static final String TIMELINE_SERVICE_CLIENT_RETRY_INTERVAL_MS = TIMELINE_SERVICE_CLIENT_PREFIX
            + "retry-interval-ms";

    public static final long DEFAULT_TIMELINE_SERVICE_CLIENT_RETRY_INTERVAL_MS = 1000;

    /** Timeline client policy for whether connections are fatal */
    public static final String TIMELINE_SERVICE_CLIENT_BEST_EFFORT = TIMELINE_SERVICE_CLIENT_PREFIX + "best-effort";

    public static final boolean DEFAULT_TIMELINE_SERVICE_CLIENT_BEST_EFFORT = false;

    /** Flag to enable recovery of timeline service */
    public static final String TIMELINE_SERVICE_RECOVERY_ENABLED = TIMELINE_SERVICE_PREFIX + "recovery.enabled";
    public static final boolean DEFAULT_TIMELINE_SERVICE_RECOVERY_ENABLED = false;

    /** Timeline service state store class */
    public static final String TIMELINE_SERVICE_STATE_STORE_CLASS = TIMELINE_SERVICE_PREFIX + "state-store-class";

    public static final String TIMELINE_SERVICE_LEVELDB_STATE_STORE_PREFIX = TIMELINE_SERVICE_PREFIX
            + "leveldb-state-store.";

    /** Timeline service state store leveldb path */
    public static final String TIMELINE_SERVICE_LEVELDB_STATE_STORE_PATH = TIMELINE_SERVICE_LEVELDB_STATE_STORE_PREFIX
            + "path";

    // Timeline delegation token related keys
    public static final String TIMELINE_DELEGATION_KEY_UPDATE_INTERVAL = TIMELINE_SERVICE_PREFIX
            + "delegation.key.update-interval";
    public static final long DEFAULT_TIMELINE_DELEGATION_KEY_UPDATE_INTERVAL = 24 * 60 * 60 * 1000; // 1 day
    public static final String TIMELINE_DELEGATION_TOKEN_RENEW_INTERVAL = TIMELINE_SERVICE_PREFIX
            + "delegation.token.renew-interval";
    public static final long DEFAULT_TIMELINE_DELEGATION_TOKEN_RENEW_INTERVAL = 24 * 60 * 60 * 1000; // 1 day
    public static final String TIMELINE_DELEGATION_TOKEN_MAX_LIFETIME = TIMELINE_SERVICE_PREFIX
            + "delegation.token.max-lifetime";
    public static final long DEFAULT_TIMELINE_DELEGATION_TOKEN_MAX_LIFETIME = 7 * 24 * 60 * 60 * 1000; // 7 days

    // Timeline service v2 offlien aggregation related keys
    public static final String TIMELINE_OFFLINE_AGGREGATION_PREFIX = YarnConfiguration.TIMELINE_SERVICE_PREFIX
            + "aggregation.offline.";
    public static final String PHOENIX_OFFLINE_STORAGE_CONN_STR = TIMELINE_OFFLINE_AGGREGATION_PREFIX
            + "phoenix.connectionString";

    public static final String PHOENIX_OFFLINE_STORAGE_CONN_STR_DEFAULT = "jdbc:phoenix:localhost:2181:/hbase";

    // ///////////////////////////////
    // Shared Cache Configs
    // ///////////////////////////////
    public static final String SHARED_CACHE_PREFIX = "yarn.sharedcache.";

    // common configs
    /** whether the shared cache is enabled/disabled */
    public static final String SHARED_CACHE_ENABLED = SHARED_CACHE_PREFIX + "enabled";
    public static final boolean DEFAULT_SHARED_CACHE_ENABLED = false;

    /** The config key for the shared cache root directory. */
    public static final String SHARED_CACHE_ROOT = SHARED_CACHE_PREFIX + "root-dir";
    public static final String DEFAULT_SHARED_CACHE_ROOT = "/sharedcache";

    /** The config key for the level of nested directories before getting to the
     * checksum directory. */
    public static final String SHARED_CACHE_NESTED_LEVEL = SHARED_CACHE_PREFIX + "nested-level";
    public static final int DEFAULT_SHARED_CACHE_NESTED_LEVEL = 3;

    // Shared Cache Manager Configs

    public static final String SCM_STORE_PREFIX = SHARED_CACHE_PREFIX + "store.";

    public static final String SCM_STORE_CLASS = SCM_STORE_PREFIX + "class";
    public static final String DEFAULT_SCM_STORE_CLASS = "org.apache.hadoop.yarn.server.sharedcachemanager.store.InMemorySCMStore";

    public static final String SCM_APP_CHECKER_CLASS = SHARED_CACHE_PREFIX + "app-checker.class";
    public static final String DEFAULT_SCM_APP_CHECKER_CLASS = "org.apache.hadoop.yarn.server.sharedcachemanager.RemoteAppChecker";

    /** The address of the SCM admin interface. */
    public static final String SCM_ADMIN_ADDRESS = SHARED_CACHE_PREFIX + "admin.address";
    public static final int DEFAULT_SCM_ADMIN_PORT = 8047;
    public static final String DEFAULT_SCM_ADMIN_ADDRESS = "0.0.0.0:" + DEFAULT_SCM_ADMIN_PORT;

    /** Number of threads used to handle SCM admin interface. */
    public static final String SCM_ADMIN_CLIENT_THREAD_COUNT = SHARED_CACHE_PREFIX + "admin.thread-count";
    public static final int DEFAULT_SCM_ADMIN_CLIENT_THREAD_COUNT = 1;

    /** The address of the SCM web application. */
    public static final String SCM_WEBAPP_ADDRESS = SHARED_CACHE_PREFIX + "webapp.address";
    public static final int DEFAULT_SCM_WEBAPP_PORT = 8788;
    public static final String DEFAULT_SCM_WEBAPP_ADDRESS = "0.0.0.0:" + DEFAULT_SCM_WEBAPP_PORT;

    // In-memory SCM store configuration

    public static final String IN_MEMORY_STORE_PREFIX = SCM_STORE_PREFIX + "in-memory.";

    /**
     * A resource in the InMemorySCMStore is considered stale if the time since
     * the last reference exceeds the staleness period. This value is specified in
     * minutes.
     */
    public static final String IN_MEMORY_STALENESS_PERIOD_MINS = IN_MEMORY_STORE_PREFIX + "staleness-period-mins";
    public static final int DEFAULT_IN_MEMORY_STALENESS_PERIOD_MINS = 7 * 24 * 60;

    /**
     * Initial delay before the in-memory store runs its first check to remove
     * dead initial applications. Specified in minutes.
     */
    public static final String IN_MEMORY_INITIAL_DELAY_MINS = IN_MEMORY_STORE_PREFIX + "initial-delay-mins";
    public static final int DEFAULT_IN_MEMORY_INITIAL_DELAY_MINS = 10;

    /**
     * The frequency at which the in-memory store checks to remove dead initial
     * applications. Specified in minutes.
     */
    public static final String IN_MEMORY_CHECK_PERIOD_MINS = IN_MEMORY_STORE_PREFIX + "check-period-mins";
    public static final int DEFAULT_IN_MEMORY_CHECK_PERIOD_MINS = 12 * 60;

    // SCM Cleaner service configuration

    private static final String SCM_CLEANER_PREFIX = SHARED_CACHE_PREFIX + "cleaner.";

    /**
     * The frequency at which a cleaner task runs. Specified in minutes.
     */
    public static final String SCM_CLEANER_PERIOD_MINS = SCM_CLEANER_PREFIX + "period-mins";
    public static final int DEFAULT_SCM_CLEANER_PERIOD_MINS = 24 * 60;

    /**
     * Initial delay before the first cleaner task is scheduled. Specified in
     * minutes.
     */
    public static final String SCM_CLEANER_INITIAL_DELAY_MINS = SCM_CLEANER_PREFIX + "initial-delay-mins";
    public static final int DEFAULT_SCM_CLEANER_INITIAL_DELAY_MINS = 10;

    /**
     * The time to sleep between processing each shared cache resource. Specified
     * in milliseconds.
     */
    public static final String SCM_CLEANER_RESOURCE_SLEEP_MS = SCM_CLEANER_PREFIX + "resource-sleep-ms";
    public static final long DEFAULT_SCM_CLEANER_RESOURCE_SLEEP_MS = 0L;

    /** The address of the node manager interface in the SCM. */
    public static final String SCM_UPLOADER_SERVER_ADDRESS = SHARED_CACHE_PREFIX + "uploader.server.address";
    public static final int DEFAULT_SCM_UPLOADER_SERVER_PORT = 8046;
    public static final String DEFAULT_SCM_UPLOADER_SERVER_ADDRESS = "0.0.0.0:" + DEFAULT_SCM_UPLOADER_SERVER_PORT;

    /**
     * The number of SCM threads used to handle notify requests from the node
     * manager.
     */
    public static final String SCM_UPLOADER_SERVER_THREAD_COUNT = SHARED_CACHE_PREFIX
            + "uploader.server.thread-count";
    public static final int DEFAULT_SCM_UPLOADER_SERVER_THREAD_COUNT = 50;

    /** The address of the client interface in the SCM. */
    public static final String SCM_CLIENT_SERVER_ADDRESS = SHARED_CACHE_PREFIX + "client-server.address";
    public static final int DEFAULT_SCM_CLIENT_SERVER_PORT = 8045;
    public static final String DEFAULT_SCM_CLIENT_SERVER_ADDRESS = "0.0.0.0:" + DEFAULT_SCM_CLIENT_SERVER_PORT;

    /** The number of threads used to handle shared cache manager requests. */
    public static final String SCM_CLIENT_SERVER_THREAD_COUNT = SHARED_CACHE_PREFIX + "client-server.thread-count";
    public static final int DEFAULT_SCM_CLIENT_SERVER_THREAD_COUNT = 50;

    /** the checksum algorithm implementation **/
    public static final String SHARED_CACHE_CHECKSUM_ALGO_IMPL = SHARED_CACHE_PREFIX + "checksum.algo.impl";
    public static final String DEFAULT_SHARED_CACHE_CHECKSUM_ALGO_IMPL = "org.apache.hadoop.yarn.sharedcache.ChecksumSHA256Impl";

    // node manager (uploader) configs
    /**
     * The replication factor for the node manager uploader for the shared cache.
     */
    public static final String SHARED_CACHE_NM_UPLOADER_REPLICATION_FACTOR = SHARED_CACHE_PREFIX
            + "nm.uploader.replication.factor";
    public static final int DEFAULT_SHARED_CACHE_NM_UPLOADER_REPLICATION_FACTOR = 10;

    public static final String SHARED_CACHE_NM_UPLOADER_THREAD_COUNT = SHARED_CACHE_PREFIX
            + "nm.uploader.thread-count";
    public static final int DEFAULT_SHARED_CACHE_NM_UPLOADER_THREAD_COUNT = 20;

    ////////////////////////////////
    // Federation Configs
    ////////////////////////////////

    public static final String FEDERATION_PREFIX = YARN_PREFIX + "federation.";

    public static final String FEDERATION_ENABLED = FEDERATION_PREFIX + "enabled";
    public static final boolean DEFAULT_FEDERATION_ENABLED = false;

    public static final String FEDERATION_FAILOVER_ENABLED = FEDERATION_PREFIX + "failover.enabled";
    public static final boolean DEFAULT_FEDERATION_FAILOVER_ENABLED = true;

    public static final String FEDERATION_STATESTORE_CLIENT_CLASS = FEDERATION_PREFIX + "state-store.class";

    public static final String DEFAULT_FEDERATION_STATESTORE_CLIENT_CLASS = "org.apache.hadoop.yarn.server.federation.store.impl.MemoryFederationStateStore";

    public static final String FEDERATION_CACHE_TIME_TO_LIVE_SECS = FEDERATION_PREFIX + "cache-ttl.secs";
    // 5 minutes
    public static final int DEFAULT_FEDERATION_CACHE_TIME_TO_LIVE_SECS = 5 * 60;

    public static final String FEDERATION_FLUSH_CACHE_FOR_RM_ADDR = FEDERATION_PREFIX + "flush-cache-for-rm-addr";
    public static final boolean DEFAULT_FEDERATION_FLUSH_CACHE_FOR_RM_ADDR = true;

    public static final String FEDERATION_REGISTRY_BASE_KEY = FEDERATION_PREFIX + "registry.base-dir";
    public static final String DEFAULT_FEDERATION_REGISTRY_BASE_KEY = "yarnfederation/";

    public static final String FEDERATION_STATESTORE_HEARTBEAT_INTERVAL_SECS = FEDERATION_PREFIX
            + "state-store.heartbeat-interval-secs";

    // 5 minutes
    public static final int DEFAULT_FEDERATION_STATESTORE_HEARTBEAT_INTERVAL_SECS = 5 * 60;

    public static final String FEDERATION_MACHINE_LIST = FEDERATION_PREFIX + "machine-list";

    public static final String FEDERATION_CLUSTER_RESOLVER_CLASS = FEDERATION_PREFIX + "subcluster-resolver.class";
    public static final String DEFAULT_FEDERATION_CLUSTER_RESOLVER_CLASS = "org.apache.hadoop.yarn.server.federation.resolver."
            + "DefaultSubClusterResolverImpl";

    // the maximum wait time for the first async heartbeat response
    public static final String FEDERATION_AMRMPROXY_HB_MAX_WAIT_MS = FEDERATION_PREFIX
            + "amrmproxy.hb.maximum.wait.ms";
    public static final long DEFAULT_FEDERATION_AMRMPROXY_HB_MAX_WAIT_MS = 5000;

    // AMRMProxy split-merge timeout for active sub-clusters. We will not route
    // new asks to expired sub-clusters.
    public static final String FEDERATION_AMRMPROXY_SUBCLUSTER_TIMEOUT = FEDERATION_PREFIX
            + "amrmproxy.subcluster.timeout.ms";
    public static final long DEFAULT_FEDERATION_AMRMPROXY_SUBCLUSTER_TIMEOUT = 60000; // one minute

    public static final String DEFAULT_FEDERATION_POLICY_KEY = "*";
    public static final String FEDERATION_POLICY_MANAGER = FEDERATION_PREFIX + "policy-manager";

    public static final String DEFAULT_FEDERATION_POLICY_MANAGER = "org.apache"
            + ".hadoop.yarn.server.federation.policies" + ".manager.UniformBroadcastPolicyManager";

    public static final String FEDERATION_POLICY_MANAGER_PARAMS = FEDERATION_PREFIX + "policy-manager-params";

    public static final String DEFAULT_FEDERATION_POLICY_MANAGER_PARAMS = "";

    public static final String FEDERATION_STATESTORE_ZK_PREFIX = FEDERATION_PREFIX + "zk-state-store.";
    /** Parent znode path under which ZKRMStateStore will create znodes. */
    public static final String FEDERATION_STATESTORE_ZK_PARENT_PATH = FEDERATION_STATESTORE_ZK_PREFIX
            + "parent-path";
    public static final String DEFAULT_FEDERATION_STATESTORE_ZK_PARENT_PATH = "/federationstore";

    private static final String FEDERATION_STATESTORE_SQL_PREFIX = FEDERATION_PREFIX + "state-store.sql.";

    public static final String FEDERATION_STATESTORE_SQL_USERNAME = FEDERATION_STATESTORE_SQL_PREFIX + "username";

    public static final String FEDERATION_STATESTORE_SQL_PASSWORD = FEDERATION_STATESTORE_SQL_PREFIX + "password";

    public static final String FEDERATION_STATESTORE_SQL_URL = FEDERATION_STATESTORE_SQL_PREFIX + "url";

    public static final String FEDERATION_STATESTORE_SQL_JDBC_CLASS = FEDERATION_STATESTORE_SQL_PREFIX
            + "jdbc-class";

    public static final String DEFAULT_FEDERATION_STATESTORE_SQL_JDBC_CLASS = "org.hsqldb.jdbc.JDBCDataSource";

    public static final String FEDERATION_STATESTORE_SQL_MAXCONNECTIONS = FEDERATION_STATESTORE_SQL_PREFIX
            + "max-connections";

    public static final int DEFAULT_FEDERATION_STATESTORE_SQL_MAXCONNECTIONS = 1;

    public static final String ROUTER_PREFIX = YARN_PREFIX + "router.";

    public static final String ROUTER_BIND_HOST = ROUTER_PREFIX + "bind-host";

    public static final String ROUTER_CLIENTRM_PREFIX = ROUTER_PREFIX + "clientrm.";

    public static final String ROUTER_CLIENTRM_ADDRESS = ROUTER_CLIENTRM_PREFIX + "address";
    public static final int DEFAULT_ROUTER_CLIENTRM_PORT = 8050;
    public static final String DEFAULT_ROUTER_CLIENTRM_ADDRESS = "0.0.0.0:" + DEFAULT_ROUTER_CLIENTRM_PORT;

    public static final String ROUTER_CLIENTRM_INTERCEPTOR_CLASS_PIPELINE = ROUTER_CLIENTRM_PREFIX
            + "interceptor-class.pipeline";
    public static final String DEFAULT_ROUTER_CLIENTRM_INTERCEPTOR_CLASS = "org.apache.hadoop.yarn.server.router.clientrm."
            + "DefaultClientRequestInterceptor";

    public static final String ROUTER_PIPELINE_CACHE_MAX_SIZE = ROUTER_PREFIX + "pipeline.cache-max-size";
    public static final int DEFAULT_ROUTER_PIPELINE_CACHE_MAX_SIZE = 25;

    public static final String ROUTER_RMADMIN_PREFIX = ROUTER_PREFIX + "rmadmin.";

    public static final String ROUTER_RMADMIN_ADDRESS = ROUTER_RMADMIN_PREFIX + "address";
    public static final int DEFAULT_ROUTER_RMADMIN_PORT = 8052;
    public static final String DEFAULT_ROUTER_RMADMIN_ADDRESS = "0.0.0.0:" + DEFAULT_ROUTER_RMADMIN_PORT;

    public static final String ROUTER_RMADMIN_INTERCEPTOR_CLASS_PIPELINE = ROUTER_RMADMIN_PREFIX
            + "interceptor-class.pipeline";
    public static final String DEFAULT_ROUTER_RMADMIN_INTERCEPTOR_CLASS = "org.apache.hadoop.yarn.server.router.rmadmin."
            + "DefaultRMAdminRequestInterceptor";

    /**
     * The number of retries for GetNewApplication and SubmitApplication in
     * {@code FederationClientInterceptor}.
     */
    public static final String ROUTER_CLIENTRM_SUBMIT_RETRY = ROUTER_PREFIX + "submit.retry";
    public static final int DEFAULT_ROUTER_CLIENTRM_SUBMIT_RETRY = 3;

    public static final String ROUTER_WEBAPP_PREFIX = ROUTER_PREFIX + "webapp.";

    public static final String ROUTER_USER_CLIENT_THREADS_SIZE = ROUTER_PREFIX + "interceptor.user.threadpool-size";

    public static final int DEFAULT_ROUTER_USER_CLIENT_THREADS_SIZE = 5;

    /** The address of the Router web application. */
    public static final String ROUTER_WEBAPP_ADDRESS = ROUTER_WEBAPP_PREFIX + "address";

    public static final int DEFAULT_ROUTER_WEBAPP_PORT = 8089;
    public static final String DEFAULT_ROUTER_WEBAPP_ADDRESS = "0.0.0.0:" + DEFAULT_ROUTER_WEBAPP_PORT;

    /** The https address of the Router web application. */
    public static final String ROUTER_WEBAPP_HTTPS_ADDRESS = ROUTER_WEBAPP_PREFIX + "https.address";

    public static final int DEFAULT_ROUTER_WEBAPP_HTTPS_PORT = 8091;
    public static final String DEFAULT_ROUTER_WEBAPP_HTTPS_ADDRESS = "0.0.0.0:" + DEFAULT_ROUTER_WEBAPP_HTTPS_PORT;

    public static final String ROUTER_WEBAPP_INTERCEPTOR_CLASS_PIPELINE = ROUTER_WEBAPP_PREFIX
            + "interceptor-class.pipeline";
    public static final String DEFAULT_ROUTER_WEBAPP_INTERCEPTOR_CLASS = "org.apache.hadoop.yarn.server.router.webapp."
            + "DefaultRequestInterceptorREST";

    /**
     * The interceptor class used in FederationInterceptorREST to communicate with
     * each SubCluster.
     */
    public static final String ROUTER_WEBAPP_DEFAULT_INTERCEPTOR_CLASS = ROUTER_WEBAPP_PREFIX
            + "default-interceptor-class";
    public static final String DEFAULT_ROUTER_WEBAPP_DEFAULT_INTERCEPTOR_CLASS = "org.apache.hadoop.yarn.server.router.webapp."
            + "DefaultRequestInterceptorREST";

    /**
     * The interceptor class used in FederationInterceptorREST should return
     * partial AppReports.
     */
    public static final String ROUTER_WEBAPP_PARTIAL_RESULTS_ENABLED = ROUTER_WEBAPP_PREFIX
            + "partial-result.enabled";
    public static final boolean DEFAULT_ROUTER_WEBAPP_PARTIAL_RESULTS_ENABLED = false;

    ////////////////////////////////
    // Other Configs
    ////////////////////////////////

    public static final String YARN_REGISTRY_CLASS = YARN_PREFIX + "registry.class";
    public static final String DEFAULT_YARN_REGISTRY_CLASS = "org.apache.hadoop.registry.client.impl.FSRegistryOperationsService";

    /**
     * Use YARN_CLIENT_APPLICATION_CLIENT_PROTOCOL_POLL_INTERVAL_MS instead.
     * The interval of the yarn client's querying application state after
     * application submission. The unit is millisecond.
     */
    @Deprecated
    public static final String YARN_CLIENT_APP_SUBMISSION_POLL_INTERVAL_MS = YARN_PREFIX
            + "client.app-submission.poll-interval";

    /**
     * The interval that the yarn client library uses to poll the completion
     * status of the asynchronous API of application client protocol.
     */
    public static final String YARN_CLIENT_APPLICATION_CLIENT_PROTOCOL_POLL_INTERVAL_MS = YARN_PREFIX
            + "client.application-client-protocol.poll-interval-ms";
    public static final long DEFAULT_YARN_CLIENT_APPLICATION_CLIENT_PROTOCOL_POLL_INTERVAL_MS = 200;

    /**
     * The duration that the yarn client library waits, cumulatively across polls,
     * for an expected state change to occur. Defaults to -1, which indicates no
     * limit.
     */
    public static final String YARN_CLIENT_APPLICATION_CLIENT_PROTOCOL_POLL_TIMEOUT_MS = YARN_PREFIX
            + "client.application-client-protocol.poll-timeout-ms";
    public static final long DEFAULT_YARN_CLIENT_APPLICATION_CLIENT_PROTOCOL_POLL_TIMEOUT_MS = -1;

    /**
     * Max number of threads in NMClientAsync to process container management
     * events
     */
    public static final String NM_CLIENT_ASYNC_THREAD_POOL_MAX_SIZE = YARN_PREFIX
            + "client.nodemanager-client-async.thread-pool-max-size";
    public static final int DEFAULT_NM_CLIENT_ASYNC_THREAD_POOL_MAX_SIZE = 500;

    /**
     * Maximum number of proxy connections to cache for node managers. If set
     * to a value greater than zero then the cache is enabled and the NMClient
     * and MRAppMaster will cache the specified number of node manager proxies.
     * There will be at max one proxy per node manager. Ex. configuring it to a
     * value of 5 will make sure that client will at max have 5 proxies cached
     * with 5 different node managers. These connections for these proxies will
     * be timed out if idle for more than the system wide idle timeout period.
     * Note that this could cause issues on large clusters as many connections
     * could linger simultaneously and lead to a large number of connection
     * threads. The token used for authentication will be used only at
     * connection creation time. If a new token is received then the earlier
     * connection should be closed in order to use the new token. This and
     * {@link YarnConfiguration#NM_CLIENT_ASYNC_THREAD_POOL_MAX_SIZE} are related
     * and should be in sync (no need for them to be equal).
     * If the value of this property is zero then the connection cache is
     * disabled and connections will use a zero idle timeout to prevent too
     * many connection threads on large clusters.
     */
    public static final String NM_CLIENT_MAX_NM_PROXIES = YARN_PREFIX + "client.max-cached-nodemanagers-proxies";
    public static final int DEFAULT_NM_CLIENT_MAX_NM_PROXIES = 0;

    /** Max time to wait to establish a connection to NM */
    public static final String CLIENT_NM_CONNECT_MAX_WAIT_MS = YARN_PREFIX
            + "client.nodemanager-connect.max-wait-ms";
    public static final long DEFAULT_CLIENT_NM_CONNECT_MAX_WAIT_MS = 3 * 60 * 1000;

    /** Time interval between each attempt to connect to NM */
    public static final String CLIENT_NM_CONNECT_RETRY_INTERVAL_MS = YARN_PREFIX
            + "client.nodemanager-connect.retry-interval-ms";
    public static final long DEFAULT_CLIENT_NM_CONNECT_RETRY_INTERVAL_MS = 10 * 1000;

    public static final String YARN_HTTP_POLICY_KEY = YARN_PREFIX + "http.policy";
    public static final String YARN_HTTP_POLICY_DEFAULT = HttpConfig.Policy.HTTP_ONLY.name();

    /**
     * Max time to wait for NM to connection to RM.
     * When not set, proxy will fall back to use value of
     * RESOURCEMANAGER_CONNECT_MAX_WAIT_MS.
     */
    public static final String NM_RESOURCEMANAGER_CONNECT_MAX_WAIT_MS = YARN_PREFIX
            + "nodemanager.resourcemanager.connect.max-wait.ms";

    /**
     * Time interval between each NM attempt to connection to RM.
     * When not set, proxy will fall back to use value of
     * RESOURCEMANAGER_CONNECT_RETRY_INTERVAL_MS.
     */
    public static final String NM_RESOURCEMANAGER_CONNECT_RETRY_INTERVAL_MS = YARN_PREFIX
            + "nodemanager.resourcemanager.connect.retry-interval.ms";

    /**
     * Node-labels configurations
     */
    public static final String NODE_LABELS_PREFIX = YARN_PREFIX + "node-labels.";

    /** Node label store implementation class */
    public static final String FS_NODE_LABELS_STORE_IMPL_CLASS = NODE_LABELS_PREFIX + "fs-store.impl.class";
    public static final String DEFAULT_FS_NODE_LABELS_STORE_IMPL_CLASS = "org.apache.hadoop.yarn.nodelabels.FileSystemNodeLabelsStore";

    /** URI for NodeLabelManager */
    public static final String FS_NODE_LABELS_STORE_ROOT_DIR = NODE_LABELS_PREFIX + "fs-store.root-dir";

    /**
     * Node-attribute configurations.
     */
    public static final String NODE_ATTRIBUTE_PREFIX = YARN_PREFIX + "node-attribute.";
    /**
     * Node attribute store implementation class.
     */
    public static final String FS_NODE_ATTRIBUTE_STORE_IMPL_CLASS = NODE_ATTRIBUTE_PREFIX + "fs-store.impl.class";
    /**
     * File system node attribute store directory.
     */
    public static final String FS_NODE_ATTRIBUTE_STORE_ROOT_DIR = NODE_ATTRIBUTE_PREFIX + "fs-store.root-dir";

    /**
     * Flag to indicate if the node labels feature enabled, by default it's
     * disabled
     */
    public static final String NODE_LABELS_ENABLED = NODE_LABELS_PREFIX + "enabled";
    public static final boolean DEFAULT_NODE_LABELS_ENABLED = false;

    public static final String NODELABEL_CONFIGURATION_TYPE = NODE_LABELS_PREFIX + "configuration-type";

    public static final String CENTRALIZED_NODELABEL_CONFIGURATION_TYPE = "centralized";

    public static final String DELEGATED_CENTALIZED_NODELABEL_CONFIGURATION_TYPE = "delegated-centralized";

    public static final String DISTRIBUTED_NODELABEL_CONFIGURATION_TYPE = "distributed";

    public static final String DEFAULT_NODELABEL_CONFIGURATION_TYPE = CENTRALIZED_NODELABEL_CONFIGURATION_TYPE;

    public static final String MAX_CLUSTER_LEVEL_APPLICATION_PRIORITY = YARN_PREFIX
            + "cluster.max-application-priority";

    public static final int DEFAULT_CLUSTER_LEVEL_APPLICATION_PRIORITY = 0;

    public static final String APP_ATTEMPT_DIAGNOSTICS_LIMIT_KC = YARN_PREFIX + "app.attempt.diagnostics.limit.kc";

    public static final int DEFAULT_APP_ATTEMPT_DIAGNOSTICS_LIMIT_KC = 64;

    @Private
    public static boolean isDistributedNodeLabelConfiguration(Configuration conf) {
        return DISTRIBUTED_NODELABEL_CONFIGURATION_TYPE
                .equals(conf.get(NODELABEL_CONFIGURATION_TYPE, DEFAULT_NODELABEL_CONFIGURATION_TYPE));
    }

    @Private
    public static boolean isCentralizedNodeLabelConfiguration(Configuration conf) {
        return CENTRALIZED_NODELABEL_CONFIGURATION_TYPE
                .equals(conf.get(NODELABEL_CONFIGURATION_TYPE, DEFAULT_NODELABEL_CONFIGURATION_TYPE));
    }

    @Private
    public static boolean isDelegatedCentralizedNodeLabelConfiguration(Configuration conf) {
        return DELEGATED_CENTALIZED_NODELABEL_CONFIGURATION_TYPE
                .equals(conf.get(NODELABEL_CONFIGURATION_TYPE, DEFAULT_NODELABEL_CONFIGURATION_TYPE));
    }

    @Private
    public static boolean areNodeLabelsEnabled(Configuration conf) {
        return conf.getBoolean(NODE_LABELS_ENABLED, DEFAULT_NODE_LABELS_ENABLED);
    }

    private static final String NM_NODE_LABELS_PREFIX = NM_PREFIX + "node-labels.";

    private static final String NM_NODE_ATTRIBUTES_PREFIX = NM_PREFIX + "node-attributes.";

    public static final String NM_NODE_LABELS_PROVIDER_CONFIG = NM_NODE_LABELS_PREFIX + "provider";

    public static final String NM_NODE_ATTRIBUTES_PROVIDER_CONFIG = NM_NODE_ATTRIBUTES_PREFIX + "provider";

    // whitelist names for the yarn.nodemanager.node-labels.provider
    public static final String CONFIG_NODE_DESCRIPTOR_PROVIDER = "config";
    public static final String SCRIPT_NODE_DESCRIPTOR_PROVIDER = "script";

    private static final String NM_NODE_LABELS_PROVIDER_PREFIX = NM_NODE_LABELS_PREFIX + "provider.";

    private static final String NM_NODE_ATTRIBUTES_PROVIDER_PREFIX = NM_NODE_ATTRIBUTES_PREFIX + "provider.";

    public static final String NM_NODE_LABELS_RESYNC_INTERVAL = NM_NODE_LABELS_PREFIX + "resync-interval-ms";

    public static final long DEFAULT_NM_NODE_LABELS_RESYNC_INTERVAL = 2 * 60 * 1000;

    // If -1 is configured then no timer task should be created
    public static final String NM_NODE_LABELS_PROVIDER_FETCH_INTERVAL_MS = NM_NODE_LABELS_PROVIDER_PREFIX
            + "fetch-interval-ms";

    public static final String NM_NODE_LABELS_PROVIDER_FETCH_TIMEOUT_MS = NM_NODE_LABELS_PROVIDER_PREFIX
            + "fetch-timeout-ms";

    // once in 10 mins
    public static final long DEFAULT_NM_NODE_LABELS_PROVIDER_FETCH_INTERVAL_MS = 10 * 60 * 1000;

    // Twice of default interval time
    public static final long DEFAULT_NM_NODE_LABELS_PROVIDER_FETCH_TIMEOUT_MS = DEFAULT_NM_NODE_LABELS_PROVIDER_FETCH_INTERVAL_MS
            * 2;

    public static final String NM_PROVIDER_CONFIGURED_NODE_PARTITION = NM_NODE_LABELS_PROVIDER_PREFIX
            + "configured-node-partition";

    public static final String NM_PROVIDER_CONFIGURED_NODE_ATTRIBUTES = NM_NODE_ATTRIBUTES_PROVIDER_PREFIX
            + "configured-node-attributes";

    private static final String RM_NODE_LABELS_PREFIX = RM_PREFIX + "node-labels.";

    public static final String RM_NODE_LABELS_PROVIDER_CONFIG = RM_NODE_LABELS_PREFIX + "provider";

    private static final String RM_NODE_LABELS_PROVIDER_PREFIX = RM_NODE_LABELS_PREFIX + "provider.";

    //If -1 is configured then no timer task should be created
    public static final String RM_NODE_LABELS_PROVIDER_FETCH_INTERVAL_MS = RM_NODE_LABELS_PROVIDER_PREFIX
            + "fetch-interval-ms";

    //once in 30 mins
    public static final long DEFAULT_RM_NODE_LABELS_PROVIDER_FETCH_INTERVAL_MS = 30 * 60 * 1000;

    @Private
    /**
     * This is a private feature that isn't supposed to be used by end-users.
     */
    public static final String AM_SCHEDULING_NODE_BLACKLISTING_ENABLED = RM_PREFIX
            + "am-scheduling.node-blacklisting-enabled";
    @Private
    public static final boolean DEFAULT_AM_SCHEDULING_NODE_BLACKLISTING_ENABLED = false;

    @Private
    /**
     * This is a private feature that isn't supposed to be used by end-users.
     */
    public static final String AM_SCHEDULING_NODE_BLACKLISTING_DISABLE_THRESHOLD = RM_PREFIX
            + "am-scheduling.node-blacklisting-disable-threshold";
    @Private
    public static final float DEFAULT_AM_SCHEDULING_NODE_BLACKLISTING_DISABLE_THRESHOLD = 0.2f;

    private static final String NM_SCRIPT_BASED_NODE_LABELS_PROVIDER_PREFIX = NM_NODE_LABELS_PROVIDER_PREFIX
            + "script.";

    public static final String NM_SCRIPT_BASED_NODE_LABELS_PROVIDER_PATH = NM_SCRIPT_BASED_NODE_LABELS_PROVIDER_PREFIX
            + "path";

    public static final String NM_SCRIPT_BASED_NODE_LABELS_PROVIDER_SCRIPT_OPTS = NM_SCRIPT_BASED_NODE_LABELS_PROVIDER_PREFIX
            + "opts";

    /**
     * Node attribute provider fetch attributes interval and timeout.
     */
    public static final String NM_NODE_ATTRIBUTES_PROVIDER_FETCH_INTERVAL_MS = NM_NODE_ATTRIBUTES_PROVIDER_PREFIX
            + "fetch-interval-ms";

    public static final long DEFAULT_NM_NODE_ATTRIBUTES_PROVIDER_FETCH_INTERVAL_MS = 10 * 60 * 1000;

    public static final String NM_NODE_ATTRIBUTES_PROVIDER_FETCH_TIMEOUT_MS = NM_NODE_ATTRIBUTES_PROVIDER_PREFIX
            + "fetch-timeout-ms";

    public static final long DEFAULT_NM_NODE_ATTRIBUTES_PROVIDER_FETCH_TIMEOUT_MS = DEFAULT_NM_NODE_ATTRIBUTES_PROVIDER_FETCH_INTERVAL_MS
            * 2;

    /**
     * Script to collect node attributes.
     */
    private static final String NM_SCRIPT_BASED_NODE_ATTRIBUTES_PROVIDER_PREFIX = NM_NODE_ATTRIBUTES_PROVIDER_PREFIX
            + "script.";

    public static final String NM_SCRIPT_BASED_NODE_ATTRIBUTES_PROVIDER_PATH = NM_SCRIPT_BASED_NODE_ATTRIBUTES_PROVIDER_PREFIX
            + "path";

    public static final String NM_SCRIPT_BASED_NODE_ATTRIBUTES_PROVIDER_OPTS = NM_SCRIPT_BASED_NODE_ATTRIBUTES_PROVIDER_PREFIX
            + "opts";

    /*
     * Support to view apps for given user in secure cluster.
     * @deprecated This field is deprecated for {@link #FILTER_ENTITY_LIST_BY_USER}
     */
    @Deprecated
    public static final String DISPLAY_APPS_FOR_LOGGED_IN_USER = RM_PREFIX + "display.per-user-apps";

    public static final String FILTER_ENTITY_LIST_BY_USER = "yarn.webapp.filter-entity-list-by-user";
    public static final boolean DEFAULT_DISPLAY_APPS_FOR_LOGGED_IN_USER = false;

    // RM and NM CSRF props
    public static final String REST_CSRF = "webapp.rest-csrf.";
    public static final String RM_CSRF_PREFIX = RM_PREFIX + REST_CSRF;
    public static final String NM_CSRF_PREFIX = NM_PREFIX + REST_CSRF;
    public static final String TIMELINE_CSRF_PREFIX = TIMELINE_SERVICE_PREFIX + REST_CSRF;
    public static final String RM_CSRF_ENABLED = RM_CSRF_PREFIX + "enabled";
    public static final String NM_CSRF_ENABLED = NM_CSRF_PREFIX + "enabled";
    public static final String TIMELINE_CSRF_ENABLED = TIMELINE_CSRF_PREFIX + "enabled";
    public static final String RM_CSRF_CUSTOM_HEADER = RM_CSRF_PREFIX + "custom-header";
    public static final String NM_CSRF_CUSTOM_HEADER = NM_CSRF_PREFIX + "custom-header";
    public static final String TIMELINE_CSRF_CUSTOM_HEADER = TIMELINE_CSRF_PREFIX + "custom-header";
    public static final String RM_CSRF_METHODS_TO_IGNORE = RM_CSRF_PREFIX + "methods-to-ignore";
    public static final String NM_CSRF_METHODS_TO_IGNORE = NM_CSRF_PREFIX + "methods-to-ignore";
    public static final String TIMELINE_CSRF_METHODS_TO_IGNORE = TIMELINE_CSRF_PREFIX + "methods-to-ignore";

    // RM and NM XFS props
    public static final String XFS = "webapp.xfs-filter.";
    public static final String YARN_XFS_ENABLED = "yarn." + XFS + "enabled";
    public static final String RM_XFS_PREFIX = RM_PREFIX + XFS;
    public static final String NM_XFS_PREFIX = NM_PREFIX + XFS;
    public static final String TIMELINE_XFS_PREFIX = TIMELINE_SERVICE_PREFIX + XFS;
    public static final String RM_XFS_OPTIONS = RM_XFS_PREFIX + "xframe-options";
    public static final String NM_XFS_OPTIONS = NM_XFS_PREFIX + "xframe-options";
    public static final String TIMELINE_XFS_OPTIONS = TIMELINE_XFS_PREFIX + "xframe-options";

    /**
     * Settings for timeline reader.
     */
    public static final String TIMELINE_SERVICE_READER_BIND_HOST = TIMELINE_SERVICE_READER_PREFIX + "bind-host";

    public static final String TIMELINE_SERVICE_READER_WEBAPP_ADDRESS = TIMELINE_SERVICE_READER_PREFIX
            + "webapp.address";
    public static final String DEFAULT_TIMELINE_SERVICE_READER_WEBAPP_ADDRESS = DEFAULT_TIMELINE_SERVICE_WEBAPP_ADDRESS;

    public static final String TIMELINE_SERVICE_READER_WEBAPP_HTTPS_ADDRESS = TIMELINE_SERVICE_READER_PREFIX
            + "webapp.https.address";
    public static final String DEFAULT_TIMELINE_SERVICE_READER_WEBAPP_HTTPS_ADDRESS = DEFAULT_TIMELINE_SERVICE_WEBAPP_HTTPS_ADDRESS;

    @Private
    public static final String TIMELINE_SERVICE_READER_STORAGE_MONITOR_INTERVAL_MS = TIMELINE_SERVICE_READER_PREFIX
            + "storage-monitor.interval-ms";
    public static final long DEFAULT_TIMELINE_SERVICE_STORAGE_MONITOR_INTERVAL_MS = 60 * 1000;

    /**
     * Marked collector properties as Private since it run as auxillary service.
     */
    public static final String TIMELINE_SERVICE_COLLECTOR_PREFIX = TIMELINE_SERVICE_PREFIX + "collector.";

    @Private
    public static final String TIMELINE_SERVICE_COLLECTOR_BIND_HOST = TIMELINE_SERVICE_COLLECTOR_PREFIX
            + "bind-host";

    @Private
    public static final String TIMELINE_SERVICE_COLLECTOR_WEBAPP_ADDRESS = TIMELINE_SERVICE_COLLECTOR_PREFIX
            + "webapp.address";
    public static final String DEFAULT_TIMELINE_SERVICE_COLLECTOR_WEBAPP_ADDRESS = DEFAULT_TIMELINE_SERVICE_WEBAPP_ADDRESS;

    @Private
    public static final String TIMELINE_SERVICE_COLLECTOR_WEBAPP_HTTPS_ADDRESS = TIMELINE_SERVICE_COLLECTOR_PREFIX
            + "webapp.https.address";
    public static final String DEFAULT_TIMELINE_SERVICE_COLLECTOR_WEBAPP_HTTPS_ADDRESS = DEFAULT_TIMELINE_SERVICE_WEBAPP_HTTPS_ADDRESS;

    /**
     * Settings for NUMA awareness.
     */
    public static final String NM_NUMA_AWARENESS_ENABLED = NM_PREFIX + "numa-awareness.enabled";
    public static final boolean DEFAULT_NM_NUMA_AWARENESS_ENABLED = false;
    public static final String NM_NUMA_AWARENESS_READ_TOPOLOGY = NM_PREFIX + "numa-awareness.read-topology";
    public static final boolean DEFAULT_NM_NUMA_AWARENESS_READ_TOPOLOGY = false;
    public static final String NM_NUMA_AWARENESS_NODE_IDS = NM_PREFIX + "numa-awareness.node-ids";
    public static final String NM_NUMA_AWARENESS_NUMACTL_CMD = NM_PREFIX + "numa-awareness.numactl.cmd";
    public static final String DEFAULT_NM_NUMA_AWARENESS_NUMACTL_CMD = "/usr/bin/numactl";

    public YarnConfiguration() {
        super();
    }

    public YarnConfiguration(Configuration conf) {
        super(conf);
        if (!(conf instanceof YarnConfiguration)) {
            this.reloadConfiguration();
        }
    }

    @Private
    public static List<String> getServiceAddressConfKeys(Configuration conf) {
        return useHttps(conf) ? RM_SERVICES_ADDRESS_CONF_KEYS_HTTPS : RM_SERVICES_ADDRESS_CONF_KEYS_HTTP;
    }

    /**
     * Get the socket address for <code>name</code> property as a
     * <code>InetSocketAddress</code>. On an HA cluster,
     * this fetches the address corresponding to the RM identified by
     * {@link #RM_HA_ID}.
     * @param name property name.
     * @param defaultAddress the default value
     * @param defaultPort the default port
     * @return InetSocketAddress
     */
    @Override
    public InetSocketAddress getSocketAddr(String name, String defaultAddress, int defaultPort) {
        String address;
        if (HAUtil.isHAEnabled(this) && getServiceAddressConfKeys(this).contains(name)) {
            address = HAUtil.getConfValueForRMInstance(name, defaultAddress, this);
        } else {
            address = get(name, defaultAddress);
        }
        return NetUtils.createSocketAddr(address, defaultPort, name);
    }

    @Override
    public InetSocketAddress updateConnectAddr(String name, InetSocketAddress addr) {
        String prefix = name;
        if (HAUtil.isHAEnabled(this) && getServiceAddressConfKeys(this).contains(name)) {
            prefix = HAUtil.addSuffix(prefix, HAUtil.getRMHAId(this));
        }
        return super.updateConnectAddr(prefix, addr);
    }

    @Private
    public static int getRMDefaultPortNumber(String addressPrefix, Configuration conf) {
        if (addressPrefix.equals(YarnConfiguration.RM_ADDRESS)) {
            return YarnConfiguration.DEFAULT_RM_PORT;
        } else if (addressPrefix.equals(YarnConfiguration.RM_SCHEDULER_ADDRESS)) {
            return YarnConfiguration.DEFAULT_RM_SCHEDULER_PORT;
        } else if (addressPrefix.equals(YarnConfiguration.RM_WEBAPP_ADDRESS)) {
            return YarnConfiguration.DEFAULT_RM_WEBAPP_PORT;
        } else if (addressPrefix.equals(YarnConfiguration.RM_WEBAPP_HTTPS_ADDRESS)) {
            return YarnConfiguration.DEFAULT_RM_WEBAPP_HTTPS_PORT;
        } else if (addressPrefix.equals(YarnConfiguration.RM_RESOURCE_TRACKER_ADDRESS)) {
            return YarnConfiguration.DEFAULT_RM_RESOURCE_TRACKER_PORT;
        } else if (addressPrefix.equals(YarnConfiguration.RM_ADMIN_ADDRESS)) {
            return YarnConfiguration.DEFAULT_RM_ADMIN_PORT;
        } else {
            throw new HadoopIllegalArgumentException("Invalid RM RPC address Prefix: " + addressPrefix
                    + ". The valid value should be one of " + getServiceAddressConfKeys(conf));
        }
    }

    public static boolean useHttps(Configuration conf) {
        return HttpConfig.Policy.HTTPS_ONLY == HttpConfig.Policy
                .fromString(conf.get(YARN_HTTP_POLICY_KEY, YARN_HTTP_POLICY_DEFAULT));
    }

    public static boolean shouldRMFailFast(Configuration conf) {
        return conf.getBoolean(YarnConfiguration.RM_FAIL_FAST,
                conf.getBoolean(YarnConfiguration.YARN_FAIL_FAST, YarnConfiguration.DEFAULT_YARN_FAIL_FAST));
    }

    @Private
    public static String getClusterId(Configuration conf) {
        String clusterId = conf.get(YarnConfiguration.RM_CLUSTER_ID);
        if (clusterId == null) {
            throw new HadoopIllegalArgumentException(
                    "Configuration doesn't specify " + YarnConfiguration.RM_CLUSTER_ID);
        }
        return clusterId;
    }

    public static boolean isDistSchedulingEnabled(Configuration conf) {
        return conf.getBoolean(YarnConfiguration.DIST_SCHEDULING_ENABLED,
                YarnConfiguration.DEFAULT_DIST_SCHEDULING_ENABLED);
    }

    public static boolean isOpportunisticContainerAllocationEnabled(Configuration conf) {
        return conf.getBoolean(YarnConfiguration.OPPORTUNISTIC_CONTAINER_ALLOCATION_ENABLED,
                YarnConfiguration.DEFAULT_OPPORTUNISTIC_CONTAINER_ALLOCATION_ENABLED);
    }

    // helper methods for timeline service configuration
    /**
     * Returns whether the timeline service is enabled via configuration.
     *
     * @param conf the configuration
     * @return whether the timeline service is enabled.
     */
    public static boolean timelineServiceEnabled(Configuration conf) {
        return conf.getBoolean(YarnConfiguration.TIMELINE_SERVICE_ENABLED,
                YarnConfiguration.DEFAULT_TIMELINE_SERVICE_ENABLED);
    }

    /**
     * Returns the timeline service version. It does not check whether the
     * timeline service itself is enabled.
     *
     * @param conf the configuration
     * @return the timeline service version as a float.
     */
    public static float getTimelineServiceVersion(Configuration conf) {
        return conf.getFloat(TIMELINE_SERVICE_VERSION, DEFAULT_TIMELINE_SERVICE_VERSION);
    }

    /**
     * Returns whether the timeline service v.2 is enabled via configuration.
     *
     * @param conf the configuration
     * @return whether the timeline service v.2 is enabled. V.2 refers to a
     * version greater than equal to 2 but smaller than 3.
     */
    public static boolean timelineServiceV2Enabled(Configuration conf) {
        boolean enabled = false;
        if (timelineServiceEnabled(conf)) {
            Collection<Float> versions = getTimelineServiceVersions(conf);
            for (Float version : versions) {
                if (version.intValue() == 2) {
                    enabled = true;
                    break;
                }
            }
        }
        return enabled;
    }

    /**
     * Returns whether the timeline service v.1 is enabled via configuration.
     *
     * @param conf the configuration
     * @return whether the timeline service v.1 is enabled. V.1 refers to a
     * version greater than equal to 1 but smaller than 2.
     */
    public static boolean timelineServiceV1Enabled(Configuration conf) {
        boolean enabled = false;
        if (timelineServiceEnabled(conf)) {
            Collection<Float> versions = getTimelineServiceVersions(conf);
            for (Float version : versions) {
                if (version.intValue() == 1) {
                    enabled = true;
                    break;
                }
            }
        }
        return enabled;
    }

    /**
     * Returns whether the timeline service v.1,5 is enabled via configuration.
     *
     * @param conf the configuration
     * @return whether the timeline service v.1.5 is enabled. V.1.5 refers to a
     * version equal to 1.5.
     */
    public static boolean timelineServiceV15Enabled(Configuration conf) {
        boolean enabled = false;
        if (timelineServiceEnabled(conf)) {
            Collection<Float> versions = getTimelineServiceVersions(conf);
            for (Float version : versions) {
                if (Float.compare(version, 1.5f) == 0) {
                    enabled = true;
                    break;
                }
            }
        }
        return enabled;
    }

    /**
     * Returns all the active timeline service versions. It does not check
     * whether the timeline service itself is enabled.
     *
     * @param conf the configuration
     * @return the timeline service versions as a collection of floats.
     */
    private static Collection<Float> getTimelineServiceVersions(Configuration conf) {
        String versions = conf.get(TIMELINE_SERVICE_VERSIONS);
        if (versions == null) {
            versions = Float.toString(getTimelineServiceVersion(conf));
        }
        List<String> stringList = Arrays.asList(versions.split(","));
        List<Float> floatList = new ArrayList<Float>();
        for (String s : stringList) {
            Float f = Float.parseFloat(s);
            floatList.add(f);
        }
        return floatList;
    }

    /**
     * Returns whether the system publisher is enabled.
     *
     * @param conf the configuration
     * @return whether the system publisher is enabled.
     */
    public static boolean systemMetricsPublisherEnabled(Configuration conf) {
        return conf.getBoolean(YarnConfiguration.SYSTEM_METRICS_PUBLISHER_ENABLED,
                YarnConfiguration.DEFAULT_SYSTEM_METRICS_PUBLISHER_ENABLED);
    }

    /**
     * Returns whether the NUMA awareness is enabled.
     *
     * @param conf the configuration
     * @return whether the NUMA awareness is enabled.
     */
    public static boolean numaAwarenessEnabled(Configuration conf) {
        return conf.getBoolean(NM_NUMA_AWARENESS_ENABLED, DEFAULT_NM_NUMA_AWARENESS_ENABLED);
    }

    /* For debugging. mp configurations to system output as XML format. */
    public static void main(String[] args) throws Exception {
        new YarnConfiguration(new Configuration()).writeXml(System.out);
    }
}