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https://issues.apache.org/jira/browse/YARN-4280?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kuhu Shukla updated YARN-4280:
------------------------------
    Attachment: YARN-4280.002.patch

Updated patch for failing test which was due to my patch using addTo() to 
Resources.none(). Fixed checkstyles/javac warnings.

> CapacityScheduler reservations may not prevent indefinite postponement on a 
> busy cluster
> ----------------------------------------------------------------------------------------
>
>                 Key: YARN-4280
>                 URL: https://issues.apache.org/jira/browse/YARN-4280
>             Project: Hadoop YARN
>          Issue Type: Bug
>          Components: capacity scheduler
>    Affects Versions: 2.6.1, 2.8.0, 2.7.1
>            Reporter: Kuhu Shukla
>            Assignee: Kuhu Shukla
>         Attachments: YARN-4280.001.patch, YARN-4280.002.patch
>
>
> Consider the following scenario:
> There are 2 queues A(25% of the total capacity) and B(75%), both can run at 
> total cluster capacity. There are 2 applications, appX that runs on Queue A, 
> always asking for 1G containers(non-AM) and appY runs on Queue B asking for 2 
> GB containers.
> The user limit is high enough for the application to reach 100% of the 
> cluster resource. 
> appX is running at total cluster capacity, full with 1G containers releasing 
> only one container at a time. appY comes in with a request of 2GB container 
> but only 1 GB is free. Ideally, since appY is in the underserved queue, it 
> has higher priority and should reserve for its 2 GB request. Since this 
> request puts the alloc+reserve above total capacity of the cluster, 
> reservation is not made. appX comes in with a 1GB request and since 1GB is 
> still available, the request is allocated. 
> This can continue indefinitely causing priority inversion.



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