[jira] [Created] (MAPREDUCE-6251) JobClient needs additional retries at a higher level to address not-immediately-consistent dfs corner cases

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

Craig Welch created MAPREDUCE-6251:
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             Summary: JobClient needs additional retries at a higher level to address not-immediately-consistent dfs corner cases
                 Key: MAPREDUCE-6251
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6251
             Project: Hadoop Map/Reduce
          Issue Type: Bug
          Components: jobhistoryserver
    Affects Versions: 2.2.0
            Reporter: Craig Welch
            Assignee: Craig Welch


The JobClient is used to get job status information for running and completed jobs.  Final state and history for a job is communicated from the application master to the job history server via a distributed file system - where the history is uploaded by the application master to the dfs and then scanned/loaded by the jobhistory server.  While HDFS has strong consistency guarantees not all Hadoop DFS's do.  When used in conjunction with a distributed file system which does not have this guarantee there will be cases where the history server may not see an uploaded file, resulting in the dreaded "no such job" and a null value for the RunningJob in the client.



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