Fengdong Yu created MAPREDUCE-4857:
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Summary: Fix 126 error during map/reduce phase
Key: MAPREDUCE-4857
URL: https://issues.apache.org/jira/browse/MAPREDUCE-4857
Project: Hadoop Map/Reduce
Issue Type: Bug
Affects Versions: 1.0.4
Reporter: Fengdong Yu
Fix For: 1.0.4
There is rare happenings during map or reduce phase, but mostly in map phase,
the Exception messages:
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 126.
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
and error logs are cleaned, so It's very hard to debug.
but I compared DefaultTaskController.java with 0.22, they use "bash command" to
start the job scritp, but 1.0.4 use "bash, "-c", command".
I removed "-c", everything is ok, 126 error code never happen again.
I read man document of bash, it indicates when fork a new thread with write
command, another thread with "bash -c" also has a writable fd. so it could
return 126 status occasionally.
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