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https://issues.apache.org/jira/browse/YARN-3510?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14563983#comment-14563983
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Craig Welch commented on YARN-3510:
-----------------------------------
The attached patch supports an optional configuration option for the preemption
policy, {code}
yarn.resourcemanager.monitor.capacity.preemption.preempt_evenly{code}, which
(when set to true) causes the policy to only preempt one live container per
application per round, and to do multiple rounds until the desired resources
are obtained (or no further progress is occurring), so that preemption should
generally maintain existing relative usage between apps. This is in contrast
to the default behavior (when unset or set to false) (equivalent to the
existing behavior), which is to take as much as possible from each app in order
of the preemption iterator. The default works well for the fifo case, but will
unbalance usage between apps in the fair case.
> Create an extension of ProportionalCapacityPreemptionPolicy which preempts a
> number of containers from each application in a way which respects fairness
> --------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: YARN-3510
> URL: https://issues.apache.org/jira/browse/YARN-3510
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: yarn
> Reporter: Craig Welch
> Assignee: Craig Welch
> Attachments: YARN-3510.2.patch
>
>
> The ProportionalCapacityPreemptionPolicy preempts as many containers from
> applications as it can during it's preemption run. For fifo this makes
> sense, as it is prempting in reverse order & therefore maintaining the
> primacy of the "oldest". For fair ordering this does not have the desired
> effect - instead, it should preempt a number of containers from each
> application which maintains a fair balance /close to a fair balance between
> them
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