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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:
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Attachment: YARN-4280.005.patch
Revised patch to address comments by Jason. This approach eliminates the need
to store blockedResource and instead uses childLimits.headroom when a
QUEUE_SKIPPED allocation state is received, for determining what resource limit
should be passed down to the next childQueue. Also, the 'skipped' boolean is
extended in CSAssignment into an enum reflecting the skippedType which would be
OTHER_SKIPPED for legacy skipped=true, QUEUE_LIMIT_SKIPPED for our 'blocked'
case, NO_SKIPPED otherwise.
> 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,
> YARN-4280.003.patch, YARN-4280.004.patch, YARN-4280.005.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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