[
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)
