13/05/12 03:05:35 INFO mapreduce.Job: Job job_1368318686284_0013 failed with state FAILED due to: Job commit failed: java.io.IOException:
1. Set user credentials for the job (config change)
2. Submit a MapReduce job (feature start)
When calling the FileOutputCommitter, it cannot initialize the user credentials.
As AM did not get user credentials from UGI during initialization, the credentials cannot be reached in job submission.
During the initialization of AM, it does not get user credentials from UGI.
Semantic --- this is a case where the catastrophic failure is not caused by incorrect handling. The user got an exception, which resulted in termination. The root cause is that this exception should not be thrown in the first place. The handling was correct.