[jira] [Commented] (YARN-4462) FairScheduler: Disallow preemption from a queue

["Karthik Kambatla (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/YARN-4462?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15096959#comment-15096959 ] 

Karthik Kambatla commented on YARN-4462:
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Thanks for working on this, [~Tao Jie]. The approach looks good to me. Comments on the patch itself:
# We should make the config less ambiguous. When we say disable preemption, it is not clear we are disabling preempting for/from the queue. I would like to be as explicit as possible. How about a config that is more descriptive - allowPreemptionFrom or preemptionFrom. This could take true or false to conform with other FairScheduler configs. Also, it would be nice to have a global option, so folks could pick a default enable/disable based on the number of queues they have.
# Would like the fields and methods updated accordingly. For instance, FairSchedulerQueueInfo and FSQueue could have isPreemptable instead of isPreemptionDisabled. 
# FSQueue#setPreemptionDisabled is not used anywhere
# Can we move the new test added to TestFairSchedulerPreemption. We should move the rest of them also, but may be that is better done on a separate JIRA.
# Can we also add a test to verify the behavior where preemption is disabled on all queues? 


> FairScheduler: Disallow preemption from a queue
> -----------------------------------------------
>
>                 Key: YARN-4462
>                 URL: https://issues.apache.org/jira/browse/YARN-4462
>             Project: Hadoop YARN
>          Issue Type: Improvement
>          Components: fairscheduler
>    Affects Versions: 2.6.0
>            Reporter: Tao Jie
>            Assignee: Tao Jie
>         Attachments: YARN-4462.001.patch, YARN-4462.002.patch, YARN-4462.003.patch
>
>
> When scheduler preemption is enabled, applications could be preempted if they obtain resource over they should take. 
> When a mapreduce application is preempted some resource, it just runs slower. However, when the preempted application is a long-run service, such as tomcat running in slider, the service would fail.
> So we should have a flag for application to indicate the scheduler that those application should not be preempted. 



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