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https://issues.apache.org/jira/browse/YARN-4148?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14743358#comment-14743358
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Jun Gong commented on YARN-4148:
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I have some thoughts.
Proposal A: NM records its total resource and available resource. When
launching a container, NM checks available resource and waits until there is
enough resource for container. But there might be a time gap from AM's
perspective, AM thinks it has launched container, however container might be
waiting for its resource.
Proposal B: RM does not release app's resource until containers actually finish
and NM releases the resource. It seems a little complex.
I prefer proposal A. Any suggestion or feedback is greatly appreciated.
> When killing app, RM releases app's resource before they are released by NM
> ---------------------------------------------------------------------------
>
> Key: YARN-4148
> URL: https://issues.apache.org/jira/browse/YARN-4148
> Project: Hadoop YARN
> Issue Type: Bug
> Components: resourcemanager
> Reporter: Jun Gong
> Assignee: Jun Gong
>
> When killing a app, RM scheduler releases app's resource as soon as possible,
> then it might allocate these resource for new requests. But NM have not
> released them at that time.
> The problem was found when we supported GPU as a resource(YARN-4122). Test
> environment: a NM had 6 GPUs, app A used all 6 GPUs, app B was requesting 3
> GPUs. Killed app A, then RM released A's 6 GPUs, and allocated 3 GPUs to B.
> But when B tried to start container on NM, NM found it didn't have 3 GPUs to
> allocate because it had not released A's GPUs.
> I think the problem also exists for CPU/Memory. It might cause OOM when
> memory is overused.
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