zhaoyunjiong created MAPREDUCE-4843:
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Summary: When using DefaultTaskController, JobLocalizer not thread
safe
Key: MAPREDUCE-4843
URL: https://issues.apache.org/jira/browse/MAPREDUCE-4843
Project: Hadoop Map/Reduce
Issue Type: Bug
Components: tasktracker
Affects Versions: 1.1.1
Reporter: zhaoyunjiong
Priority: Critical
In our cluster, some times job will failed due to below exception:
Error initializing attempt_201210181806_18566_r_000376_0:
org.apache.hadoop.util.DiskChecker$DiskErrorException: Could not find
taskTracker/$username/jobcache/job_201210181806_18566/job.xml in any of the
configured local directories at
org.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.getLocalPathToRead(LocalDirAllocator.java:424)
The root cause is JobLocalizer is not thread safe.
In DefaultTaskController.initializeJob method:
JobLocalizer localizer = new JobLocalizer((JobConf)getConf(), user, jobid);
but in JobLocalizer, it just simply keep the reference of the conf.
When two TaskLauncher threads(mapLauncher and reduceLauncher) try to
initializeJob at same time, it will have two JobLocalizer, but one conf
instance.
So some times ttConf.setStrings(JOB_LOCAL_CTXT, localDirs) will reset previous
job's conf.
It will cause the previous job's job.xml stored at another user's dir.
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