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Hadoop: How to obtain the exception actually failed the job on Mapper or Reducer at runtime?

+2 votes
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Does anyone knows how to ‘capture’ the exception which actually failed the job running on Mapper or Reducer at runtime? It seems Hadoop is designed to be fault tolerant that the failed jobs will be automatically rerun for a certain amount of times and won’t actually expose the real problem unless you look into the error log?

In my use case, I would like to capture the exception and make different response based on the type of the exception.

posted Dec 11, 2013 by Jagan Mishra

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1 Answer

+1 vote

You can check the userlogs directory where the job and attempt logs are stored. For each attempt you should have a stderr, stdout and syslog file. The first two hold the program output for each stream (useful for debug purposes), while the last contains execution details provided by the platform.

answer Dec 11, 2013 by Garima Jain
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Maybe someone already experienced similar problems / is more experienced than I am.

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