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https://issues.apache.org/jira/browse/HADOOP-3842?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12617750#action_12617750
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Steve Loughran commented on HADOOP-3842:
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What are the semantics of submitting jobs to a scheduler that does not consider
itself running? Is this a race condition in which the scheduler is responding
to RPC operations but not yet scheduling work?
The Hadoop-3412 JobTracker declares itself running in the constructor; it says
it is live, so perhaps the solution is for it not to declare its liveness until
the scheduler is live.
Note that the HADOOP-3628 lifecycle changes would move the startup of the
various services outside the constructor. I'm merging that patch with
HADOOP-3412, and will move the starting of the scheduler up to the startup phase
> There is a window where the JobTracker is in the RUNNING state (i.e ready to
> accept jobs) and never executes them.
> ------------------------------------------------------------------------------------------------------------------
>
> Key: HADOOP-3842
> URL: https://issues.apache.org/jira/browse/HADOOP-3842
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Amar Kamat
> Priority: Blocker
>
> Prior to HADOOP-3412, job tracker could accept jobs without even offering
> service (i.e without {{JobTracker.offerService()}} being called). In such a
> case the job stays in JT's memory and job execution was guaranteed. With
> HADOOP-3412, {{JobTracker.submitJob()}} adds the job to JT's local structures
> and passes it to the scheduler. Scheduler gets initialized in
> {{JobTracker.offerService()}} and hence calling {{JobTracker.submitJob()}}
> before calling {{JobTracker.offerService()}} is actually a no-op. The job
> stays in JT's memory but never gets initialized. This is
> - backward incompatible
> - erroneous as there is a window where the jobtracker is ready to accept
> jobs, accepts them and never executes them.
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