Hadoop dfs error : INFO ipc.Client: Retrying connect to server: localhost

Apparently, someone added the older hadoop(1.0.3) bin directory into the path variable before I had added the new hadoop(1.0.4) bin directory. And thus whenever I ran "hadoop" from the CLI, it executed the binaries of the older hadoop rather than the new one.

Solution:

• Remove the entire bin path of older hadoop

• Shutdown cluster - Exit terminal

• Login in new terminal session

• Startup node

• Tried hadoop dfs -ls / -> Works fine !!!! Good lesson learnt.

Looks like many people ran into this problem.

There might be no need to change /etc/hosts, and make sure you can access master and slave from each other, and your core-site.xml are the same pointing to the right master node and port number.

Then run $HADOOP/bin/stop-all.sh, $HADOOP/bin/start-all.sh on master node ONLY. (If run on slave might lead to problems). Use JPS to check whether all services are there as follows.

On master node:4353 DataNode4640 JobTracker4498 SecondaryNameNode4788 TaskTracker4989 Jps4216 NameNode

On slave node:3143 Jps2827 DataNode2960 TaskTracker

In addition, check your firewall rules between namenode and datanode