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https://issues.apache.org/jira/browse/YARN-3054?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15191556#comment-15191556
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Karthik Kambatla commented on YARN-3054:
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Also, the approach being proposed on YARN-4752 doesn't take container priority
into consideration anymore. So, we shouldn't systemic bias towards preempting
low priority containers.
> Preempt policy in FairScheduler may cause mapreduce job never finish
> --------------------------------------------------------------------
>
> Key: YARN-3054
> URL: https://issues.apache.org/jira/browse/YARN-3054
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: fairscheduler
> Affects Versions: 2.6.0
> Reporter: Peng Zhang
>
> Preemption policy is related with schedule policy now. Using comparator of
> schedule policy to find preemption candidate cannot guarantee a subset of
> containers never be preempted. And this may cause tasks to be preempted
> periodically before they finish. So job cannot make any progress.
> I think preemption in YARN should got below assurance:
> 1. Mapreduce jobs can get additional resources when others are idle;
> 2. Mapreduce jobs for one user in one queue can still progress with its min
> share when others preempt resources back.
> Maybe always preempt the latest app and container can get this?
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