Example usage for org.apache.hadoop.net DNS reverseDns

Introduction

In this page you can find the example usage for org.apache.hadoop.net DNS reverseDns.

Prototype

public static String reverseDns(InetAddress hostIp, @Nullable String ns) throws NamingException 

Source Link

Document

Returns the hostname associated with the specified IP address by the provided nameserver.

Usage

From source file:org.apache.kudu.mapreduce.KuduTableInputFormat.java

License:Apache License

/**
 * This method might seem alien, but we do this in order to resolve the hostnames the same way
 * Hadoop does. This ensures we get locality if Kudu is running along MR/YARN.
 * @param host hostname we got from the master
 * @param port port we got from the master
 * @return reverse DNS'd address//from   www . ja  va  2 s  .  co m
 */
private String reverseDNS(String host, Integer port) {
    String location = this.reverseDNSCacheMap.get(host);
    if (location != null) {
        return location;
    }
    // The below InetSocketAddress creation does a name resolution.
    InetSocketAddress isa = new InetSocketAddress(host, port);
    if (isa.isUnresolved()) {
        LOG.warn("Failed address resolve for: " + isa);
    }
    InetAddress tabletInetAddress = isa.getAddress();
    try {
        location = domainNamePointerToHostName(DNS.reverseDns(tabletInetAddress, this.nameServer));
        this.reverseDNSCacheMap.put(host, location);
    } catch (NamingException e) {
        LOG.warn("Cannot resolve the host name for " + tabletInetAddress + " because of " + e);
        location = host;
    }
    return location;
}

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From source file:org.apache.phoenix.hive.util.PhoenixStorageHandlerUtil.java

License:Apache License

private static String reverseDNS(InetAddress ipAddress) throws NamingException, UnknownHostException {
    String hostName = reverseDNSCacheMap.get(ipAddress);

    if (hostName == null) {
        String ipAddressString = null;
        try {//www . j  av  a  2 s.c  o m
            ipAddressString = DNS.reverseDns(ipAddress, null);
        } catch (Exception e) {
            // We can use InetAddress in case the jndi failed to pull up the reverse DNS entry
            // from the name service. Also, in case of ipv6, we need to use the InetAddress
            // since resolving reverse DNS using jndi doesn't work well with ipv6 addresses.
            ipAddressString = InetAddress.getByName(ipAddress.getHostAddress()).getHostName();
        }

        if (ipAddressString == null) {
            throw new UnknownHostException("No host found for " + ipAddress);
        }

        hostName = Strings.domainNamePointerToHostName(ipAddressString);
        reverseDNSCacheMap.put(ipAddress, hostName);
    }

    return hostName;
}

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From source file:org.cloudgraph.hbase.mapreduce.GraphInputFormat.java

License:Apache License

/**
 * Uses {@link InetAddress} in case of {@link DNS} lookup failure.
 * /*from   w  ww  .  java 2 s  . com*/
 * @param ipAddr
 *          the address
 * @return the reverse address
 * @throws NamingException
 * @throws UnknownHostException
 */
public String reverseDNS(InetAddress ipAddr) throws NamingException, UnknownHostException {
    String hostName = this.reverseDNSCache.get(ipAddr);
    if (hostName == null) {
        String ipAddressString = null;
        try {
            ipAddressString = DNS.reverseDns(ipAddr, null);
        } catch (Exception e) {
            ipAddressString = InetAddress.getByName(ipAddr.getHostAddress()).getHostName();
        }
        if (ipAddressString == null)
            throw new UnknownHostException("No host found for " + ipAddr);
        hostName = Strings.domainNamePointerToHostName(ipAddressString);
        this.reverseDNSCache.put(ipAddr, hostName);
    }
    return hostName;
}

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