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https://issues.apache.org/jira/browse/YARN-2592?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14146391#comment-14146391
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Jason Lowe commented on YARN-2592:
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+1 for at least allowing users to configure no preemption to satisfy over 
capacity queues.

> Preemption can kill containers to fulfil need of already over-capacity queue.
> -----------------------------------------------------------------------------
>
>                 Key: YARN-2592
>                 URL: https://issues.apache.org/jira/browse/YARN-2592
>             Project: Hadoop YARN
>          Issue Type: Bug
>    Affects Versions: 3.0.0, 2.5.1
>            Reporter: Eric Payne
>
> There are scenarios in which one over-capacity queue can cause preemption of 
> another over-capacity queue. However, since killing containers may lose work, 
> it doesn't make sense to me to kill containers to feed an already 
> over-capacity queue.
> Consider the following:
> {code}
> root has A,B,C, total capacity = 90
> A.guaranteed = 30, A.pending = 5, A.current = 40
> B.guaranteed = 30, B.pending = 0, B.current = 50
> C.guaranteed = 30, C.pending = 0, C.current = 0
> {code}
> In this case, the queue preemption monitor will kill 5 resources from queue B 
> so that queue A can pick them up, even though queue A is already over its 
> capacity. This could lose any work that those containers in B had already 
> done.
> Is there a use case for this behavior? It seems to me that if a queue is 
> already over its capacity, it shouldn't destroy the work of other queues. If 
> the over-capacity queue needs more resources, that seems to be a problem that 
> should be solved by increasing its guarantee.



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