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https://issues.apache.org/jira/browse/YARN-4711?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15197858#comment-15197858
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Naganarasimha G R commented on YARN-4711:
-----------------------------------------
Hi [~sjlee0],
Following issues needs to be fixed as part of this jira :
# Stop Retry on all exceptions
# Async calls for metrics needs to implemented
# Possible NPE in NMTimelinePublisher$ContainerEventHandler
# Possible NPE in putEntity(NMTimelinePublisher.java:213)
# Possible NPE in TimelineEntity.toString() when real is not null
and i wanted discuss in particular to Issue 3, It seems now after 3367 whether
its required to queue in Dispatcher when we are already queuing in
TimelineClient for NM side events. On further thinking thought it will be
required for only sync events as for example
{{ContainerManagerImpl.ContainerEventDispatcher.handle(ContainerEvent)}}
should not be *blocked* on sync timeline publish event. But one flaw in current
handling is, we put the event into *nmMetricsPublisher.dispatcher* in
{{nmMetricsPublisher.publishContainerEvent}}, due to this if there is any delay
in the dispatcher we might miss to publish the events.(NPE we got as in 3 point
).
So my idea was to create a ATS event to be published and wrap it in the
existing *TimelinePublishEvent* and put in the dispatcher and for metrics
directly get the apps TimelineClient and call *putEntitiesAsync*. Thoughts?
> NM is going down with NPE's due to single thread processing of events by
> Timeline client
> ----------------------------------------------------------------------------------------
>
> Key: YARN-4711
> URL: https://issues.apache.org/jira/browse/YARN-4711
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: timelineserver
> Reporter: Naganarasimha G R
> Assignee: Naganarasimha G R
> Priority: Critical
> Labels: yarn-2928-1st-milestone
> Attachments: 4711Analysis.txt
>
>
> After YARN-3367, while testing the latest 2928 branch came across few NPEs
> due to which NM is shutting down.
> {code}
> 2016-02-21 23:19:54,078 FATAL org.apache.hadoop.yarn.event.AsyncDispatcher:
> Error in dispatcher thread
> java.lang.NullPointerException
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher$ContainerEventHandler.handle(NMTimelinePublisher.java:306)
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher$ContainerEventHandler.handle(NMTimelinePublisher.java:296)
> at
> org.apache.hadoop.yarn.event.AsyncDispatcher.dispatch(AsyncDispatcher.java:183)
> at
> org.apache.hadoop.yarn.event.AsyncDispatcher$1.run(AsyncDispatcher.java:109)
> at java.lang.Thread.run(Thread.java:745)
> {code}
> {code}
> java.lang.NullPointerException
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher.putEntity(NMTimelinePublisher.java:213)
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher.publishContainerFinishedEvent(NMTimelinePublisher.java:192)
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher.access$400(NMTimelinePublisher.java:63)
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher$ApplicationEventHandler.handle(NMTimelinePublisher.java:289)
> at
> org.apache.hadoop.yarn.server.nodemanager.timelineservice.NMTimelinePublisher$ApplicationEventHandler.handle(NMTimelinePublisher.java:280)
> at
> org.apache.hadoop.yarn.event.AsyncDispatcher.dispatch(AsyncDispatcher.java:183)
> at
> org.apache.hadoop.yarn.event.AsyncDispatcher$1.run(AsyncDispatcher.java:109)
> at java.lang.Thread.run(Thread.java:745)
> {code}
> On analysis found that the there was delay in processing of events, as after
> YARN-3367 all the events were getting processed by a single thread inside the
> timeline client.
> Additionally found one scenario where there is possibility of NPE:
> * TimelineEntity.toString() when {{real}} is not null
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