Hadoop Beginner's Guide

Time for action – swapping to a new NameNode host

In the following steps we keep the new configuration files on an NFS share mounted to /share/backup and change the paths to match where you have the new files. Also use a different string to grep; we use a portion of the IP address we know isn't shared with any other host in the cluster.

1. Log on to the current NameNode host and shut down the cluster.

   $ stop-all.sh
   

2. Halt the host that runs the NameNode.

   $ sudo poweroff
   

3. Log on to the new NameNode host and confirm the new configuration files have the correct NameNode location.

   $ grep 110 /share/backup/*.xml
   

4. On the new host, first copy across the slaves file.

   $ cp /share/backup/slaves Hadoop/conf
   

5. Now copy across the updated configuration files.

   $ cp /share/backup/*site.xml ...