[jira] [Created] (MAPREDUCE-5734) Reducer preemption does not happen if node is blacklisted, intern job get hanged.

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

Rohith created MAPREDUCE-5734:
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             Summary: Reducer preemption does not  happen if node is blacklisted, intern job get hanged.
                 Key: MAPREDUCE-5734
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5734
             Project: Hadoop Map/Reduce
          Issue Type: Bug
    Affects Versions: 2.2.0
         Environment: SuSE 11 SP2 + Hadoop-2.3 
            Reporter: Rohith


There are 4 NodeManagers with 8GB each.Total cluster capacity is 32GB.Cluster slow start is set to 1.

Job is running reducer task occupied 29GB of cluster.One NodeManager(NM-4) is become unstable(3 Map got killed), MRAppMaster blacklisted unstable NodeManager(NM-4). All reducer task are running in cluster now.

MRAppMaster does not preempt the reducers because for Reducer preemption calculation, headRoom is considering blacklisted nodes memory. This makes jobs to hang forever(ResourceManager does not assing any new containers on blacklisted nodes but returns availableResouce considers cluster free memory). 





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