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Guang Yang commented on YARN-10428: ----------------------------------- {quote}getCachedUsed returns non-zero but getCachedDemand returns zero, mag will be NaN. {quote} As I mentioned in the comment in the code, this should never happen. "CachedDemand" includes "CachedUsed" ([https://github.com/apache/hadoop/blob/95dfc875d32414e81df73a6e57e6767d7cce90c3/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/ResourceUsage.java#L291).] I'm fine to change the code to be more defensive of potential bugs in other components. This is my first patch in YARN, I don't know about the guidelines. In my opinion, if mag is supposed to be non negative and we are concerned it's a negative value, we should add an assertion. Please let me know if you want to change the condition as you suggested, I'm happy to do that. Thanks for the review ! > Zombie applications in the YARN queue using FAIR + sizebasedweight > ------------------------------------------------------------------ > > Key: YARN-10428 > URL: https://issues.apache.org/jira/browse/YARN-10428 > Project: Hadoop YARN > Issue Type: Bug > Components: capacityscheduler > Affects Versions: 2.8.5 > Reporter: Guang Yang > Priority: Major > Attachments: YARN-10428.001.patch, YARN-10428.002.patch > > > Seeing zombie jobs in the YARN queue that uses FAIR and size based weight > ordering policy . > *Detection:* > The YARN UI shows incorrect number of "Num Schedulable Applications". > *Impact:* > The queue has an upper limit of number of running applications, with zombie > job, it hits the limit even though the number of running applications is far > less than the limit. > *Workaround:* > **Fail-over and restart Resource Manager process. > *Analysis:* > **In the heap dump, we can find the zombie jobs in the `FairOderingPolicy# > schedulableEntities` (see attachment). Take application > "application_1599157165858_29429" for example, it is still in the > `FairOderingPolicy#schedulableEntities` set, however, if we check the log of > resource manager, we can see RM already tried to remove the application: > > ./yarn-yarn-resourcemanager-ip-172-21-153-252.log.2020-09-04-04:2020-09-04 > 04:32:19,730 INFO > org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue > (ResourceManager Event Processor): Application removed - appId: > application_1599157165858_29429 user: svc_di_data_eng queue: core-data > #user-pending-applications: -3 #user-active-applications: 7 > #queue-pending-applications: 0 #queue-active-applications: 21 > > So it appears RM failed to removed the application from the set. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: yarn-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: yarn-issues-h...@hadoop.apache.org