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Upgrading HDFS namenode servers to CentOS 7 while HA is enabled

Upgrading HDFS namenode servers to CentOS 7 while HA is enabled

New Contributor

Hi,

 

I have Cloudera 5.16.1 with HA enabled for HDFS.

I want to upgrade OS on both NameNode servers (Active & Standby) to CentOS 7 and keep all settings.

What's the correct way to do it ?

I tried the following:

1. Backed up jn & nn folders in both NameNode servers along with other few folders

2. Stopped all services in the cluster

3. Deleted standby NameNode server from cluster and from cloudera manager

4. Reinstalled the server

5. Added server back to cluster

6. Restored files

7. Started services back

But, it failed to re-enable the HA again.

 

Please assist / advise 

1 REPLY 1
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Re: Upgrading HDFS namenode servers to CentOS 7 while HA is enabled

Mentor

@khjomaa 
Did you follow the official Cloudera OS upgrade best practice your method looks strange, I am a bit surprised and wondering all the trouble you'd go through if you had also RM , Hive Metastore HA?

 

I think you took the wrong approach, the reason you have HA is to  always have the service up and running in the event you shut down the  Active namenode it would have automatically failed over to the standby and you would have gone ahead and upgraded the OS independently of the CDH binaries  and  done with the OS upgrade  restarting that node would automatically join the cluster and become the standby . After the journalNodes have applied all the logs editlog and merged the FSImage you could forcefully or gracefully failover and proceed with the upgrade of the other node.

Upgrading Hosts With High Availability Enabled

If you have enabled high availability for the NameNode or JobTracker, follow this procedure:

  1. Stop the backup NameNode or JobTracker.
  2. Upgrade the OS partition.
  3. Start the services and ensure that they are running properly.
  4. Failover to the backup NameNode or JobTracker.
  5. Upgrade the primary NameNode or JobTracker.
  6. Bring the primary NameNode or JobTracker back online.
  7. Reverse the failover.

The above are the steps you should have taken it's from Cloudera, can you share the document you followed?
Happy hadooping 

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