[jira] [Commented] (MAPREDUCE-5329) APPLICATION_INIT is never sent to AuxServices other than the builtin ShuffleHandler

["Avner BenHanoch (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-5329?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13782879#comment-13782879 ] 

Avner BenHanoch commented on MAPREDUCE-5329:
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I would just like to make sure that you know that I am waiting for your approval for changing *mapreduce.job.shuffle.provider.plugin.classes* to *mapreduce.job.shuffle.provider.services* and for listing the *service names* instead of *service classes*.
I appreciate your help.

> APPLICATION_INIT is never sent to AuxServices other than the builtin ShuffleHandler
> -----------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-5329
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5329
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: mr-am
>    Affects Versions: 2.1.0-beta, 2.0.6-alpha
>            Reporter: Avner BenHanoch
>             Fix For: trunk
>
>         Attachments: MAPREDUCE-5329.patch
>
>
> APPLICATION_INIT is never sent to AuxServices other than the built-in ShuffleHandler.  This means that 3rd party ShuffleProvider(s) will not be able to function, because APPLICATION_INIT enables the AuxiliaryService to map jobId->userId. This is needed for properly finding the MOFs of a job per reducers' requests.
> NOTE: The built-in ShuffleHandler does get APPLICATION_INIT events due to hard-coded expression in hadoop code. The current TaskAttemptImpl.java code explicitly call: serviceData.put (ShuffleHandler.MAPREDUCE_SHUFFLE_SERVICEID, ...) and ignores any additional AuxiliaryService. As a result, only the built-in ShuffleHandler will get APPLICATION_INIT events.  Any 3rd party AuxillaryService will never get APPLICATION_INIT events.
> I think a solution can be in one of two ways:
> 1. Change TaskAttemptImpl.java to loop on all Auxiliary Services and register each of them, by calling serviceData.put (…) in loop.
> 2. Change AuxServices.java similar to the fix in: MAPREDUCE-2668  "APPLICATION_STOP is never sent to AuxServices".  This means that in case the 'handle' method gets APPLICATION_INIT event it will demultiplex it to all Aux Services regardless of the value in event.getServiceID().
> I prefer the 2nd solution.  I am welcoming any ideas.  I can provide the needed patch for any option that people like.
> See [Pluggable Shuffle in Hadoop documentation|http://hadoop.apache.org/docs/current/hadoop-mapreduce-client/hadoop-mapreduce-client-core/PluggableShuffleAndPluggableSort.html]



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