[MAPREDUCE-1397] NullPointerException observed during task failures

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.20.1
• Fix Version/s: 0.21.0
• Component/s: tasktracker
• Hadoop Flags: Reviewed
• Release Note: Fixed a race condition involving JvmRunner.kill() and KillTaskAction, which was leading to an NullPointerException causing a transient inconsistent state in JvmManager and failure of tasks.
• Assignee: Amareshwari Sriramadasu
• Reporter: Ramya Sunil
• Created: 22/Jan/10 10:36
• Updated: 20/May/13 15:26
• Resolved: 27/Apr/10 10:03

Description

In an environment where many jobs are killed simultaneously, NPEs are observed in the TT/JT logs when a task fails. The situation is aggravated when the taskcontroller.cfg is not configured properly. Below is the exception obtained:

INFO org.apache.hadoop.mapred.TaskInProgress: Error from <attempt_ID>:
java.lang.Throwable: Child Error
        at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:529)
Caused by: java.lang.NullPointerException
        at org.apache.hadoop.mapred.JvmManager$JvmManagerForType.getDetails(JvmManager.java:329)
        at org.apache.hadoop.mapred.JvmManager$JvmManagerForType.reapJvm(JvmManager.java:315)
        at org.apache.hadoop.mapred.JvmManager$JvmManagerForType.access$000(JvmManager.java:146)
        at org.apache.hadoop.mapred.JvmManager.launchJvm(JvmManager.java:109)
        at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:502)

 

Issue Links

• relates to: MAPREDUCE-5260 Job failed because of JvmManager running into inconsistent state