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Minimum HA Components Required for Rolling Restart

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Minimum HA Components Required for Rolling Restart

Contributor

Which components must have HA in order to perform Rolling Upgrade? The documentation for Rolling Restart is a bit vague in regards to the bare minimum required to perform Rolling Upgrade:

  • HDFS HA is clearly required
  • YARN RM HA says "should be enabled to prevent a disruption in service during the upgrade" - Can Rolling Upgrade be performed without it?
  • Hive Metastore HA is "recommended". Is it required?
  • HiveServer2 and Oozie HA - are these required?

Thank you

Reference: http://docs.hortonworks.com/HDPDocuments/Ambari-2....

3 REPLIES 3
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Re: Minimum HA Components Required for Rolling Restart

Master Collaborator

HA will allow the services to be operational during upgrade. Basically HA here allows multiple service instances available on different nodes on the cluster. So while upgrading and restarting the service on one node, the other nodes running the same service will be operational. If you are sure there will be no clients connecting to these services during upgrade then you can live without HA for those services.

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Re: Minimum HA Components Required for Rolling Restart

Mentor

@Wes Floyd can you close this question as we now have Express Upgrade?

Re: Minimum HA Components Required for Rolling Restart

The clients are set to automatically retry, so technically you only need NameNode HA. Of course, if you have HA for HiveServer2, Oozie, Resource Manager, load balanced Knox servers, multiple Storm Supervisors, multiple HBASE masters, etc., then you have a stronger guarantee of uptime.

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