[
https://issues.apache.org/jira/browse/HDFS-14067?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16685894#comment-16685894
]
Plamen Jeliazkov commented on HDFS-14067:
-----------------------------------------
Hey guys,
Just want to throw in my thoughts here since I am testing this. Of course feel
free to object / criticize.
I am working off the assumption that Observer state is just an extension of
Standby state but allows reads as well.
With that assumption, I also assume that `transitionToStandby` on an already
Standby node should be a no-op, even with automatic failover enabled.
This is why I am expecting manual transition from Standby to Observer to work
even if I have automatic failover enabled.
Then the path to "automatic failover" with Observers should be, as I understand
it from design, just a matter of going from Observer->Standby->Active, when the
time comes.
Maybe we are just missing the treatment of Observer as a "double promotion" in
the automatic failover scenario?
Hope I made sense there. Thanks.
> 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.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
