[YARN-3830] AbstractYarnScheduler.createReleaseCache may try to clean a null attempt

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: scheduler
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: nijel
• Reporter: nijel
• Created: 19/Jun/15 06:03
• Updated: 30/Aug/16 01:20
• Resolved: 01/Jul/15 13:40

Description

org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnScheduler.createReleaseCache()

protected void createReleaseCache() {
    // Cleanup the cache after nm expire interval.
    new Timer().schedule(new TimerTask() {
      @Override
      public void run() {
        for (SchedulerApplication<T> app : applications.values()) {

          T attempt = app.getCurrentAppAttempt();
          synchronized (attempt) {
            for (ContainerId containerId : attempt.getPendingRelease()) {
              RMAuditLogger.logFailure(

Here the attempt can be null since the attempt is created later. So null pointer exception will come

2015-06-19 09:29:16,195 | ERROR | Timer-3 | Thread Thread[Timer-3,5,main] threw an Exception. | YarnUncaughtExceptionHandler.java:68
java.lang.NullPointerException
	at org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnScheduler$1.run(AbstractYarnScheduler.java:457)
	at java.util.TimerThread.mainLoop(Timer.java:555)
	at java.util.TimerThread.run(Timer.java:505)

This will skip the other applications in this run.
Can add a null check and continue with other applications