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https://issues.apache.org/jira/browse/YARN-8191?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16483864#comment-16483864
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Gergo Repas commented on YARN-8191:
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[~haibochen] Thanks for the review!
1) - Good point, I fixed it.
2) - This logic's origin is a suggestion from [~wilfreds] (Wilfred - please
correct me if I'm wrong about the intentions behind {{getRemovedStaticQueues(),
setQueuesToDynamic()}}). The point here is that the set of removed queues can
be gathered in {{AllocationReloadListener.onReload()}} outside of the
writeLock. It's safe to do so because onReload() is only called from the
synchronized {{AllocationFileLoaderService.reloadAllocations()}} method. This
way the {{AllocationReloadListener.getRemovedStaticQueues()}} logic is subject
to the least amount of locking. The thread safety was indeed missing for
{{QueueManager.setQueuesToDynamic()}}, I've added the missing synchronized
block.
3) Sorry, what do you mean by "What about the other case where some dynamic
queues are not added as static in the new allocation file?". If you mean
dynamic queue creation via application submission, the test case for this (+the
removal) is {{TestQueueManager.testRemovalOfDynamicLeafQueue()}}.
4-5) I have refactored this part of the code, removed
getIncompatibleQueueName() and changed only the return type of
removeEmptyIncompatibleQueues() to indicate if there was no queue that's been
tried to be removed.
6) {{updateAllocationConfiguration()}} is only called when the configuration
file has been modified, so if for example there's only one configuration
modification during the lifetime of the RM, incompatible queues would not be
cleaned up until a restart.
> Fair scheduler: queue deletion without RM restart
> -------------------------------------------------
>
> Key: YARN-8191
> URL: https://issues.apache.org/jira/browse/YARN-8191
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: fairscheduler
> Affects Versions: 3.0.1
> Reporter: Gergo Repas
> Assignee: Gergo Repas
> Priority: Major
> Attachments: Queue Deletion in Fair Scheduler.pdf,
> YARN-8191.000.patch, YARN-8191.001.patch, YARN-8191.002.patch,
> YARN-8191.003.patch, YARN-8191.004.patch, YARN-8191.005.patch,
> YARN-8191.006.patch, YARN-8191.007.patch, YARN-8191.008.patch,
> YARN-8191.009.patch, YARN-8191.010.patch, YARN-8191.011.patch,
> YARN-8191.012.patch, YARN-8191.013.patch
>
>
> The Fair Scheduler never cleans up queues even if they are deleted in the
> allocation file, or were dynamically created and are never going to be used
> again. Queues always remain in memory which leads to two following issues.
> # Steady fairshares aren’t calculated correctly due to remaining queues
> # WebUI shows deleted queues, which is confusing for users (YARN-4022).
> We want to support proper queue deletion without restarting the Resource
> Manager:
> # Static queues without any entries that are removed from fair-scheduler.xml
> should be deleted from memory.
> # Dynamic queues without any entries should be deleted.
> # RM Web UI should only show the queues defined in the scheduler at that
> point in time.
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