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https://issues.apache.org/jira/browse/YARN-11697?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17848046#comment-17848046
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Syed Shameerur Rahman commented on YARN-11697:
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[~wilfreds] any thoughts on this ?
> Fix fair scheduler race condition in removeApplicationAttempt and
> moveApplication
> ---------------------------------------------------------------------------------
>
> Key: YARN-11697
> URL: https://issues.apache.org/jira/browse/YARN-11697
> Project: Hadoop YARN
> Issue Type: Bug
> Affects Versions: 3.2.1
> Reporter: Syed Shameerur Rahman
> Assignee: Syed Shameerur Rahman
> Priority: Major
>
> For Hadoop version 3.2.1, the ResourceManager (RM) restarts frequently with
> the following exception
> {code:java}
> 2024-03-11 04:41:29,329 FATAL org.apache.hadoop.yarn.event.EventDispatcher
> (SchedulerEventDispatcher:Event Processor): Error in handling event type
> APP_ATTEMPT_REMOVED to the Event Dispatcher
> java.lang.IllegalStateException: Given app to remove
> appattempt_1706879498319_86660_000001 Alloc: <memory:0, vCores:0> does not
> exist in queue [root.tier2.livy, demand=<memory:10826752, vCores:2101>,
> running=<memory:99328, vCores:17>, share=<memory:6201984, vCores:0>, w=1.0]
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FSLeafQueue.removeApp(FSLeafQueue.java:121)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.removeApplicationAttempt(FairScheduler.java:757)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:1378)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:139)
> at
> org.apache.hadoop.yarn.event.EventDispatcher$EventProcessor.run(EventDispatcher.java:66)
> at java.lang.Thread.run(Thread.java:750)
> {code}
> The exception seems similar to the one mentioned in YARN-5136, but it looks
> like there is still some edge cases not covered by YARN-5136.
> 1. On deeper look, i could see that as mentioned in the comment here. if a
> call for a moveApplication and removeApplicationAttempt for the same attempt
> are processed in short succession the application attempt will still contain
> a queue reference but is already removed from the list of applications for
> the queue.
> 2. This can happen when
> [moveApplication|https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java#L1908]
> removes the appAttempt from the queue and
> [removeApplicationAttempt|https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java#L707]
> also tries to remove the same appAttempt from the queue.
> 3. On further checking, i could see that before doing
> [moveApplication|https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java#L1779]
> writeLock on appAttempt is taken where as for
> [removeApplicationAttempt|https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java#L665]
> , i don't see any writelock being taken which can result in race condition
> if same appAttempt is being processed.
> 4. Additionally as mentioned in the comment here when such scenario occurs
> ideally we should not take down RM.
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