[jira] [Commented] (MAPREDUCE-4843) When using DefaultTaskController, JobLocalizer not thread safe

["zhaoyunjiong (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-4843?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13509730#comment-13509730 ] 

zhaoyunjiong commented on MAPREDUCE-4843:
-----------------------------------------

The fix is very simple:

diff --git a/src/mapred/org/apache/hadoop/mapred/JobLocalizer.java b/src/mapred/org/apache/hadoop/mapred/JobLocalizer.java 
index 0802b03..625face 100644 
--- a/src/mapred/org/apache/hadoop/mapred/JobLocalizer.java 
+++ b/src/mapred/org/apache/hadoop/mapred/JobLocalizer.java 
@@ -108,7 +108,7 @@ public class JobLocalizer { 
       throw new IOException("Cannot initialize for null jobid"); 
     } 
     this.jobid = jobid; 
- this.ttConf = ttConf; 
+ this.ttConf = new JobConf(ttConf); 
     lfs = FileSystem.getLocal(ttConf).getRaw(); 
     this.localDirs = createPaths(user, localDirs); 
     ttConf.setStrings(JOB_LOCAL_CTXT, localDirs); 
                
> 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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