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https://issues.apache.org/jira/browse/HDFS-14067?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16684539#comment-16684539
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Chao Sun commented on HDFS-14067:
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Thanks [~xkrogen] and [~shv]!
bq. but is the current state of each NN tracked somewhere that could become
confused if a standby suddenly appears or disappears because of a manual
transition to/from observer?
Is the concern about that the states could be cached somewhere? or potential
conflicts between manual and auto failover, where a standby could be involved
in both?
bq. Also, you sometimes use HAServiceState.STATE_NAME, and sometimes refer
directly to the state name via the static import, can you use one or the other
throughout the patch?
Sure will fix.
bq. We should wait for HDFS-14035 here, since it adds
ClientProtocol.getHAServiceState(), which should be used here instead of
HAServiceProtocol. Otherwise we will have the same problems with delegation
token as in HDFS-14035.
Hmm why we should use {{ClientProtocol.getHAServiceState()}}? we are already
calling {{HAServiceProtocol}} methods in the state transition, so whoever calls
it should already be authenticated, is that correct?
> Allow manual failover between standby and observer
> --------------------------------------------------
>
> Key: HDFS-14067
> URL: https://issues.apache.org/jira/browse/HDFS-14067
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Chao Sun
> Assignee: Chao Sun
> Priority: Major
> Attachments: HDFS-14067-HDFS-12943.000.patch
>
>
> Currently if automatic failover is enabled in a HA environment, transition
> from standby to observer would be blocked:
> {code}
> [hdfs@*** hadoop-3.3.0-SNAPSHOT]$ bin/hdfs haadmin -transitionToObserver ha2
> Automatic failover is enabled for NameNode at ****
> Refusing to manually manage HA state, since it may cause
> a split-brain scenario or other incorrect state.
> If you are very sure you know what you are doing, please
> specify the --forcemanual flag.
> {code}
> We should allow manual transition between standby and observer in this case.
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