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https://issues.apache.org/jira/browse/YARN-128?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13462832#comment-13462832
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Robert Joseph Evans commented on YARN-128:
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The problem is that we cannot be truly backwards compatible when adding in this
feature. We have to better define the lifecycle of an AM for it to be "well
behaved" and properly handle RM recovery. I would say that if the client asks
the AM to stop it should still pause on unregister until it can successfully
unregister, or until it can mark itself as "killed" in a persistent way like
with the job history log, so that when that AM is relaunched all it has to do
is to check a file on HDFS and then unregister. Perhaps the only way to be
totally backwards compatible is for the AM to indicate when it registers if it
supports RM recovery or not. Or to avoid any race conditions when the client
launches the AM it would indicate this. If it does not (legacy AMs), then the
RM will not try to relaunch it if the AM goes down while the RM is recovering.
If it does, then the AM will always be relaunched when the RM goes down.
> Resurrect RM Restart
> ---------------------
>
> Key: YARN-128
> URL: https://issues.apache.org/jira/browse/YARN-128
> Project: Hadoop YARN
> Issue Type: Bug
> Components: resourcemanager
> Affects Versions: 2.0.0-alpha
> Reporter: Arun C Murthy
> Assignee: Bikas Saha
> Attachments: MR-4343.1.patch, RM-recovery-initial-thoughts.txt
>
>
> We should resurrect 'RM Restart' which we disabled sometime during the RM
> refactor.
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