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https://issues.apache.org/jira/browse/YARN-4743?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15519543#comment-15519543
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Zephyr Guo commented on YARN-4743:
----------------------------------
I have attached YARN-CDH5.4.7.patch. It can also apply to apache 2.6.4. Hope
this can help othre people. This patch can work on our DEV clustrer. I'd like
some advice before push to PROD cluster. I worry about whether changes would
destroy the Fair Share algorithm.
> ResourceManager crash because TimSort
> -------------------------------------
>
> Key: YARN-4743
> URL: https://issues.apache.org/jira/browse/YARN-4743
> Project: Hadoop YARN
> Issue Type: Bug
> Components: fairscheduler
> Affects Versions: 2.6.4
> Reporter: Zephyr Guo
> Assignee: Yufei Gu
> Fix For: 3.0.0-alpha1
>
> Attachments: YARN-4743-v1.patch, YARN-CDH5.4.7.patch, timsort.log
>
>
> {code}
> 2016-02-26 14:08:50,821 FATAL
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Error in
> handling event type NODE_UPDATE to the scheduler
> java.lang.IllegalArgumentException: Comparison method violates its general
> contract!
> at java.util.TimSort.mergeHi(TimSort.java:868)
> at java.util.TimSort.mergeAt(TimSort.java:485)
> at java.util.TimSort.mergeCollapse(TimSort.java:410)
> at java.util.TimSort.sort(TimSort.java:214)
> at java.util.TimSort.sort(TimSort.java:173)
> at java.util.Arrays.sort(Arrays.java:659)
> at java.util.Collections.sort(Collections.java:217)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FSLeafQueue.assignContainer(FSLeafQueue.java:316)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FSParentQueue.assignContainer(FSParentQueue.java:240)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.attemptScheduling(FairScheduler.java:1091)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.nodeUpdate(FairScheduler.java:989)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:1185)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:112)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager$SchedulerEventDispatcher$EventProcessor.run(ResourceManager.java:684)
> at java.lang.Thread.run(Thread.java:745)
> 2016-02-26 14:08:50,822 INFO
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Exiting, bbye..
> {code}
> Actually, this issue found in 2.6.0-cdh5.4.7.
> I think the cause is that we modify {{Resouce}} while we are sorting
> {{runnableApps}}.
> {code:title=FSLeafQueue.java}
> Comparator<Schedulable> comparator = policy.getComparator();
> writeLock.lock();
> try {
> Collections.sort(runnableApps, comparator);
> } finally {
> writeLock.unlock();
> }
> readLock.lock();
> {code}
> {code:title=FairShareComparator}
> public int compare(Schedulable s1, Schedulable s2) {
> ......
> s1.getResourceUsage(), minShare1);
> boolean s2Needy = Resources.lessThan(RESOURCE_CALCULATOR, null,
> s2.getResourceUsage(), minShare2);
> minShareRatio1 = (double) s1.getResourceUsage().getMemory()
> / Resources.max(RESOURCE_CALCULATOR, null, minShare1,
> ONE).getMemory();
> minShareRatio2 = (double) s2.getResourceUsage().getMemory()
> / Resources.max(RESOURCE_CALCULATOR, null, minShare2,
> ONE).getMemory();
> ......
> {code}
> {{getResourceUsage}} will return current Resource. The current Resource is
> unstable.
> {code:title=FSAppAttempt.java}
> @Override
> public Resource getResourceUsage() {
> // Here the getPreemptedResources() always return zero, except in
> // a preemption round
> return Resources.subtract(getCurrentConsumption(),
> getPreemptedResources());
> }
> {code}
> {code:title=SchedulerApplicationAttempt}
> public Resource getCurrentConsumption() {
> return currentConsumption;
> }
> // This method may modify current Resource.
> public synchronized void recoverContainer(RMContainer rmContainer) {
> ......
> Resources.addTo(currentConsumption, rmContainer.getContainer()
> .getResource());
> ......
> }
> {code}
> I suggest that use stable Resource in comparator.
> Is there something i think wrong？
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