[YARN-2273] NPE in ContinuousScheduling thread when we lose a node

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.0, 2.4.1
• Fix Version/s: 2.6.0
• Component/s: fairscheduler, resourcemanager

Environment

cdh5.0.2 wheezy

• Hadoop Flags: Reviewed
• Assignee: Wei Yan
• Reporter: Andy Skelton
• Created: 10/Jul/14 18:38
• Updated: 09/Aug/15 15:07
• Resolved: 22/Jul/14 22:45

Description

One DN experienced memory errors and entered a cycle of rebooting and rejoining the cluster. After the second time the node went away, the RM produced this:

2014-07-09 21:47:36,571 INFO org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler: Application attempt appattempt_1404858438119_4352_000001 released container container_1404858438119_4352_01_000004 on node: host: node-A16-R09-19.hadoop.dfw.wordpress.com:8041 #containers=0 available=<memory:8192, vCores:8> used=<memory:0, vCores:0> with event: KILL
2014-07-09 21:47:36,571 INFO org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler: Removed node node-A16-R09-19.hadoop.dfw.wordpress.com:8041 cluster capacity: <memory:335872, vCores:328>
2014-07-09 21:47:36,571 ERROR org.apache.hadoop.yarn.YarnUncaughtExceptionHandler: Thread Thread[ContinuousScheduling,5,main] threw an Exception.
java.lang.NullPointerException
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler$NodeAvailableResourceComparator.compare(FairScheduler.java:1044)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler$NodeAvailableResourceComparator.compare(FairScheduler.java:1040)
	at java.util.TimSort.countRunAndMakeAscending(TimSort.java:329)
	at java.util.TimSort.sort(TimSort.java:203)
	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.FairScheduler.continuousScheduling(FairScheduler.java:1012)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler.access$600(FairScheduler.java:124)
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler$2.run(FairScheduler.java:1306)
	at java.lang.Thread.run(Thread.java:744)

A few cycles later YARN was crippled. The RM was running and jobs could be submitted but containers were not assigned and no progress was made. Restarting the RM resolved it.

Issue Links

• is related to: YARN-2324 Race condition in continuousScheduling for FairScheduler