[jira] [Resolved] (YARN-2592) Preemption can kill containers to fulfil need of already over-capacity queue.

["Eric Payne (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/YARN-2592?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Eric Payne resolved YARN-2592.
------------------------------
    Resolution: Invalid

> 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.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)