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https://issues.apache.org/jira/browse/YARN-1197?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13785403#comment-13785403
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Alejandro Abdelnur commented on YARN-1197:
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Bikas, makes sense, thanks for summarizing.
On the decreasing. Given that we also do a round loop AM->NM->RM->AM, Why not
make it a bit more symmetric
*AM asks RM to decrease a container
*RM notifies NM on next heartbeat about container decreasing
With this approach the RM can enforce the MIN on AM decrease and reject it if
below MIN. Also, there is not need to notify the AM of the decrease taking
place as the AM requested that. And as it is a decrease the AM can instruct the
container to shrink even if the RM does not told the NM yet. Furthermore, I
would expect an AM instructs a container to shrink before asking Yarn to avoid
a race condition that could kill the container for using more resources than it
should.
Also, by doing this there would not be difference in the free resources
bookkeeping in the RM and the NMs. Thing that may be handy not to complicate
things for YARN-311.
Thoughts?
> Support changing resources of an allocated container
> ----------------------------------------------------
>
> Key: YARN-1197
> URL: https://issues.apache.org/jira/browse/YARN-1197
> Project: Hadoop YARN
> Issue Type: Task
> Components: api, nodemanager, resourcemanager
> Affects Versions: 2.1.0-beta
> Reporter: Wangda Tan
> Attachments: yarn-1197.pdf
>
>
> Currently, YARN cannot support merge several containers in one node to a big
> container, which can make us incrementally ask resources, merge them to a
> bigger one, and launch our processes. The user scenario is described in the
> comments.
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