List the namenode and datanodes of a cluster from any node?

Question

From any node in a Hadoop cluster, what is the command to

• identify the running namenode?
• identify all running datanodes?

I have looked through the commands manual and have not found this.

Answer 1

Firstly, use the jps command to check the daemons that are running in the cluster.

To know the report of your HDFS daemons, you can execute this command:

bin/hdfs dfsadmin -report

Or 

Try to execute these commands:

hdfs getconf -namenodes

hdfs getconf -secondaryNamenodes

.. .. .. ..

If you want to know more about Hadoop, then do check out the following video tutorial: