[jira] [Commented] (YARN-5013) Allow applications to provide input on amount of locality delay to use

["Nathan Roberts (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/YARN-5013?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15263106#comment-15263106 ] 

Nathan Roberts commented on YARN-5013:
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Re-posting latest comment from [~Naganarasimha] 

Thanks for the clarification Tan, Wangda & Nathan Roberts, yes point 2 addresses the same issue and my mistake i missed to read this. And also agree to the focus of this jira to be specific to the system level OFF-SWITCH configuration.

bq.    so I think when we do the application-level support the default would need to be either unlimited or some high value, otherwise we force all applications to set this limit to something other than 1 to get decent OFF_SWITCH scheduling behavior.

Once we have system level OFF-SWITCH configuration do we require app level default also ? IIUC by default we try to make use of system level OFF-SWITCH configuration unless explicitly overridden by the app (implementation can be further discussed in that jira)

bq.    Sure, my application scheduled very quickly but my locality was terrible so I caused a lot of unnecessary cross-switch traffic. So I think we'll need some system-minimums that will prevent this type of abuse.

This point is debatable, even though i agree your point for controlling cross-switch traffic, but still the app is performing under its capacity limits so would it be good to limit it control it.

bq.    If application A meets its OFF-SWITCH-per-node limit, do we offer the node to other applications in the same queue?

any limitations if we offer the node to other applications in the same queue ? it should be fine right ?


> Allow applications to provide input on amount of locality delay to use
> ----------------------------------------------------------------------
>
>                 Key: YARN-5013
>                 URL: https://issues.apache.org/jira/browse/YARN-5013
>             Project: Hadoop YARN
>          Issue Type: Improvement
>          Components: capacity scheduler
>    Affects Versions: 3.0.0
>            Reporter: Nathan Roberts
>
> Continuing a discussion that started on YARN-4963
> It would be useful if applications could provide some input to the scheduler as to how much locality delay they'd like and/or whether they'd prefer the application to be spread wide across the cluster (as opposed to being scheduled quickly and densely).



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