[YARN-4235] FairScheduler PrimaryGroup does not handle empty groups returned for a user

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: fairscheduler
• Hadoop Flags: Reviewed
• Assignee: Anubhav Dhoot
• Reporter: Anubhav Dhoot
• Created: 07/Oct/15 19:26
• Updated: 30/Aug/16 01:15
• Resolved: 09/Oct/15 04:43

Description

We see NPE if empty groups are returned for a user. This causes a NPE and cause RM to crash as below

2015-09-22 16:51:52,780  FATAL org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Error in handling event type APP_ADDED to the scheduler
java.lang.IndexOutOfBoundsException: Index: 0
	at java.util.Collections$EmptyList.get(Collections.java:3212)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.QueuePlacementRule$PrimaryGroup.getQueueForApp(QueuePlacementRule.java:149)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.QueuePlacementRule.assignAppToQueue(QueuePlacementRule.java:74)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.QueuePlacementPolicy.assignAppToQueue(QueuePlacementPolicy.java:167)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.assignToQueue(FairScheduler.java:689)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.addApplication(FairScheduler.java:595)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:1180)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.handle(FairScheduler.java:111)
	at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager$SchedulerEventDispatcher$EventProcessor.run(ResourceManager.java:684)
	at java.lang.Thread.run(Thread.java:745)
2015-09-22 16:51:52,797  INFO org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Exiting, bbye..