[MAPREDUCE-805] Deadlock in Jobtracker

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.20.1
• Hadoop Flags: Reviewed

Release Note

Job initialization process was changed to not change (run) states during initialization. The reason is two fold
- this can lead to deadlock as state changes require circular locking (i.e JobInProgress requires JobTracker lock)
- events were not raised as these state changes were not informed/propogated back to the JobTracker

Now the JobTracker takes care of initializing/failing/killing the job and raising appropriate events. The simple rule that was enforced was that "The JobTracker lock is *must* before changing the run-state of a job".

• Assignee: Amar Kamat
• Reporter: Michael Tamm
• Created: 24/Jul/09 12:44
• Updated: 08/Dec/09 06:30
• Resolved: 11/Aug/09 10:11

Description

We are running a hadoop cluster (version 0.20.0) and have detected the following deadlock on our jobtracker:

"IPC Server handler 51 on 9001":
	at org.apache.hadoop.mapred.JobInProgress.getCounters(JobInProgress.java:943)
	- waiting to lock <0x00007f2b6fb46130> (a org.apache.hadoop.mapred.JobInProgress)
	at org.apache.hadoop.mapred.JobTracker.getJobCounters(JobTracker.java:3102)
	- locked <0x00007f2b5f026000> (a org.apache.hadoop.mapred.JobTracker)
	at sun.reflect.GeneratedMethodAccessor21.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:508)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:959)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:955)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:396)
	at org.apache.hadoop.ipc.Server$Handler.run(Server.java:953)
 "pool-1-thread-2":
	at org.apache.hadoop.mapred.JobTracker.finalizeJob(JobTracker.java:2017)
	- waiting to lock <0x00007f2b5f026000> (a org.apache.hadoop.mapred.JobTracker)
	at org.apache.hadoop.mapred.JobInProgress.garbageCollect(JobInProgress.java:2483)
	- locked <0x00007f2b6fb46130> (a org.apache.hadoop.mapred.JobInProgress)
	at org.apache.hadoop.mapred.JobInProgress.terminateJob(JobInProgress.java:2152)
	- locked <0x00007f2b6fb46130> (a org.apache.hadoop.mapred.JobInProgress)
	at org.apache.hadoop.mapred.JobInProgress.terminate(JobInProgress.java:2169)
	- locked <0x00007f2b6fb46130> (a org.apache.hadoop.mapred.JobInProgress)
	at org.apache.hadoop.mapred.JobInProgress.fail(JobInProgress.java:2245)
	- locked <0x00007f2b6fb46130> (a org.apache.hadoop.mapred.JobInProgress)
	at org.apache.hadoop.mapred.EagerTaskInitializationListener$InitJob.run(EagerTaskInitializationListener.java:86)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)

Issue Links

• duplicates: MAPREDUCE-27 Jobs with 0 maps will never get removed from the default scheduler
• relates to: MAPREDUCE-802 Simplify the job updated event notification between Jobtracker and schedulers