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 ...

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