Java tutorial
/** * Copyright 2010 The Apache Software Foundation * * 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.hbase.zookeeper; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.net.DNS; import org.apache.hadoop.util.StringUtils; import org.apache.zookeeper.server.ServerConfig; import org.apache.zookeeper.server.ZooKeeperServerMain; import org.apache.zookeeper.server.quorum.QuorumPeerConfig; import org.apache.zookeeper.server.quorum.QuorumPeerMain; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.net.InetAddress; import java.net.NetworkInterface; import java.net.UnknownHostException; import java.util.ArrayList; import java.util.Enumeration; import java.util.List; import java.util.Map.Entry; import java.util.Properties; /** * HBase's version of ZooKeeper's QuorumPeer. When HBase is set to manage * ZooKeeper, this class is used to start up QuorumPeer instances. By doing * things in here rather than directly calling to ZooKeeper, we have more * control over the process. Currently, this class allows us to parse the * zoo.cfg and inject variables from HBase's site.xml configuration in. */ public class HQuorumPeer { private static final Log LOG = LogFactory.getLog(HQuorumPeer.class); private static final String VARIABLE_START = "${"; private static final int VARIABLE_START_LENGTH = VARIABLE_START.length(); private static final String VARIABLE_END = "}"; private static final int VARIABLE_END_LENGTH = VARIABLE_END.length(); private static final int ZK_CLIENT_PORT_KEY_PREFIX_LENGTH = HConstants.ZK_CFG_PROPERTY_PREFIX.length(); /** * Parse ZooKeeper configuration from HBase XML config and run a QuorumPeer. * @param args String[] of command line arguments. Not used. */ public static void main(String[] args) { Configuration conf = HBaseConfiguration.create(); try { Properties zkProperties = makeZKProps(conf); writeMyID(zkProperties); QuorumPeerConfig zkConfig = new QuorumPeerConfig(); zkConfig.parseProperties(zkProperties); runZKServer(zkConfig); } catch (Exception e) { e.printStackTrace(); System.exit(-1); } } private static void runZKServer(QuorumPeerConfig zkConfig) throws UnknownHostException, IOException { if (zkConfig.isDistributed()) { QuorumPeerMain qp = new QuorumPeerMain(); qp.runFromConfig(zkConfig); } else { ZooKeeperServerMain zk = new ZooKeeperServerMain(); ServerConfig serverConfig = new ServerConfig(); serverConfig.readFrom(zkConfig); zk.runFromConfig(serverConfig); } } private static boolean addressIsLocalHost(String address) { return address.equals("localhost") || address.equals("127.0.0.1"); } static void writeMyID(Properties properties) throws IOException { long myId = -1; Configuration conf = HBaseConfiguration.create(); String myAddress = DNS.getDefaultHost(conf.get("hbase.zookeeper.dns.interface", "default"), conf.get("hbase.zookeeper.dns.nameserver", "default")); List<String> ips = new ArrayList<String>(); // Add what could be the best (configured) match ips.add(myAddress.contains(".") ? myAddress : StringUtils.simpleHostname(myAddress)); // For all nics get all hostnames and IPs Enumeration<?> nics = NetworkInterface.getNetworkInterfaces(); while (nics.hasMoreElements()) { Enumeration<?> rawAdrs = ((NetworkInterface) nics.nextElement()).getInetAddresses(); while (rawAdrs.hasMoreElements()) { InetAddress inet = (InetAddress) rawAdrs.nextElement(); ips.add(StringUtils.simpleHostname(inet.getHostName())); ips.add(inet.getHostAddress()); } } for (Entry<Object, Object> entry : properties.entrySet()) { String key = entry.getKey().toString().trim(); String value = entry.getValue().toString().trim(); if (key.startsWith("server.")) { int dot = key.indexOf('.'); long id = Long.parseLong(key.substring(dot + 1)); String[] parts = value.split(":"); String address = parts[0]; if (addressIsLocalHost(address) || ips.contains(address)) { myId = id; break; } } } if (myId == -1) { throw new IOException( "Could not find my address: " + myAddress + " in list of ZooKeeper quorum servers"); } String dataDirStr = properties.get("dataDir").toString().trim(); File dataDir = new File(dataDirStr); if (!dataDir.isDirectory()) { if (!dataDir.mkdirs()) { throw new IOException("Unable to create data dir " + dataDir); } } File myIdFile = new File(dataDir, "myid"); PrintWriter w = new PrintWriter(myIdFile); w.println(myId); w.close(); } /** * Make a Properties object holding ZooKeeper config equivalent to zoo.cfg. * If there is a zoo.cfg in the classpath, simply read it in. Otherwise parse * the corresponding config options from the HBase XML configs and generate * the appropriate ZooKeeper properties. * @param conf Configuration to read from. * @return Properties holding mappings representing ZooKeeper zoo.cfg file. */ public static Properties makeZKProps(Configuration conf) { // First check if there is a zoo.cfg in the CLASSPATH. If so, simply read // it and grab its configuration properties. ClassLoader cl = HQuorumPeer.class.getClassLoader(); final InputStream inputStream = cl.getResourceAsStream(HConstants.ZOOKEEPER_CONFIG_NAME); if (inputStream != null) { try { return parseZooCfg(conf, inputStream); } catch (IOException e) { LOG.warn("Cannot read " + HConstants.ZOOKEEPER_CONFIG_NAME + ", loading from XML files", e); } } // Otherwise, use the configuration options from HBase's XML files. Properties zkProperties = new Properties(); // Directly map all of the hbase.zookeeper.property.KEY properties. for (Entry<String, String> entry : conf) { String key = entry.getKey(); if (key.startsWith(HConstants.ZK_CFG_PROPERTY_PREFIX)) { String zkKey = key.substring(ZK_CLIENT_PORT_KEY_PREFIX_LENGTH); String value = entry.getValue(); // If the value has variables substitutions, need to do a get. if (value.contains(VARIABLE_START)) { value = conf.get(key); } zkProperties.put(zkKey, value); } } // If clientPort is not set, assign the default. if (zkProperties.getProperty(HConstants.CLIENT_PORT_STR) == null) { zkProperties.put(HConstants.CLIENT_PORT_STR, HConstants.DEFAULT_ZOOKEPER_CLIENT_PORT); } // Create the server.X properties. int peerPort = conf.getInt("hbase.zookeeper.peerport", 2888); int leaderPort = conf.getInt("hbase.zookeeper.leaderport", 3888); final String[] serverHosts = conf.getStrings(HConstants.ZOOKEEPER_QUORUM, "localhost"); for (int i = 0; i < serverHosts.length; ++i) { String serverHost = serverHosts[i]; String address = serverHost + ":" + peerPort + ":" + leaderPort; String key = "server." + i; zkProperties.put(key, address); } LOG.trace("Created ZK properties: " + zkProperties); return zkProperties; } /** * Return the ZK Quorum servers string given zk properties returned by * makeZKProps * @param properties * @return */ public static String getZKQuorumServersString(Properties properties) { String clientPort = null; List<String> servers = new ArrayList<String>(); // The clientPort option may come after the server.X hosts, so we need to // grab everything and then create the final host:port comma separated list. boolean anyValid = false; for (Entry<Object, Object> property : properties.entrySet()) { String key = property.getKey().toString().trim(); String value = property.getValue().toString().trim(); if (key.equals("clientPort")) { clientPort = value; } else if (key.startsWith("server.")) { String host = value.substring(0, value.indexOf(':')); servers.add(host); try { //noinspection ResultOfMethodCallIgnored InetAddress.getByName(host); anyValid = true; } catch (UnknownHostException e) { LOG.warn(StringUtils.stringifyException(e)); } } } if (!anyValid) { LOG.error("no valid quorum servers found in " + HConstants.ZOOKEEPER_CONFIG_NAME); return null; } if (clientPort == null) { LOG.error("no clientPort found in " + HConstants.ZOOKEEPER_CONFIG_NAME); return null; } if (servers.isEmpty()) { LOG.fatal("No server.X lines found in conf/zoo.cfg. HBase must have a " + "ZooKeeper cluster configured for its operation."); return null; } StringBuilder hostPortBuilder = new StringBuilder(); for (int i = 0; i < servers.size(); ++i) { String host = servers.get(i); if (i > 0) { hostPortBuilder.append(','); } hostPortBuilder.append(host); hostPortBuilder.append(':'); hostPortBuilder.append(clientPort); } return hostPortBuilder.toString(); } /** * Parse ZooKeeper's zoo.cfg, injecting HBase Configuration variables in. * This method is used for testing so we can pass our own InputStream. * @param conf HBaseConfiguration to use for injecting variables. * @param inputStream InputStream to read from. * @return Properties parsed from config stream with variables substituted. * @throws IOException if anything goes wrong parsing config */ public static Properties parseZooCfg(Configuration conf, InputStream inputStream) throws IOException { Properties properties = new Properties(); try { properties.load(inputStream); } catch (IOException e) { final String msg = "fail to read properties from " + HConstants.ZOOKEEPER_CONFIG_NAME; LOG.fatal(msg); throw new IOException(msg, e); } for (Entry<Object, Object> entry : properties.entrySet()) { String value = entry.getValue().toString().trim(); String key = entry.getKey().toString().trim(); StringBuilder newValue = new StringBuilder(); int varStart = value.indexOf(VARIABLE_START); int varEnd = 0; while (varStart != -1) { varEnd = value.indexOf(VARIABLE_END, varStart); if (varEnd == -1) { String msg = "variable at " + varStart + " has no end marker"; LOG.fatal(msg); throw new IOException(msg); } String variable = value.substring(varStart + VARIABLE_START_LENGTH, varEnd); String substituteValue = System.getProperty(variable); if (substituteValue == null) { substituteValue = conf.get(variable); } if (substituteValue == null) { String msg = "variable " + variable + " not set in system property " + "or hbase configs"; LOG.fatal(msg); throw new IOException(msg); } newValue.append(substituteValue); varEnd += VARIABLE_END_LENGTH; varStart = value.indexOf(VARIABLE_START, varEnd); } // Special case for 'hbase.cluster.distributed' property being 'true' if (key.startsWith("server.")) { if (conf.get(HConstants.CLUSTER_DISTRIBUTED).equals(HConstants.CLUSTER_IS_DISTRIBUTED) && value.startsWith("localhost")) { String msg = "The server in zoo.cfg cannot be set to localhost " + "in a fully-distributed setup because it won't be reachable. " + "See \"Getting Started\" for more information."; LOG.fatal(msg); throw new IOException(msg); } } newValue.append(value.substring(varEnd)); properties.setProperty(key, newValue.toString()); } return properties; } }