https://github.com/randomtask1155/HadoopDNSVerifier

In some cases it may not be apparent to end user how java is resolving the hostnames of the hadoop cluster nodes. This could be because of a issue with any of the following configuration settings

• /etc/sysconfig/network
• /etc/resolve.conf
• /etc/hosts

This tool is expected to be run locally on the client in question and can not be used to verify a remote clients DNS configuration settings.

##Verify the local hostname resolution

 java -classpath HadoopDNSVerifier-1.0.jar hadoop.troubleshooting.HadoopDNSVerifier.CheckLocal

Output:

  IP:10.181.22.149 hostname:hdm4.gphd.local canonicalName:hdm4.gphd.local

##Verify remote hostname resolution

 java -classpath HadoopDNSVerifier-1.0.jar hadoop.troubleshooting.HadoopDNSVerifier.CheckRemote hdm3.gphd.local

Output:

 IP:10.181.22.149 hostname:hdm3.gphd.local canonicalName:hdm3.gphd.local

#Build

 mvn package