[jira] Commented: (HADOOP-979) speculative task failure can kill jobs

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

    [ https://issues.apache.org/jira/browse/HADOOP-979?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12583028#action_12583028 ] 

Amar Kamat commented on HADOOP-979:
-----------------------------------

Can this be reproduced now?

> speculative task failure can kill jobs
> --------------------------------------
>
>                 Key: HADOOP-979
>                 URL: https://issues.apache.org/jira/browse/HADOOP-979
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>    Affects Versions: 0.11.0
>            Reporter: Owen O'Malley
>
> We had a case where the random writer example was killed by speculative execution. It happened like:
> task_0001_m_000123_0 -> starts
> task_0001_m_000123_1 -> starts and fails because attempt 0 is creating the file
> task_0001_m_000123_2 -> starts and fails because attempt 0 is creating the file
> task_0001_m_000123_3 -> starts and fails because attempt 0 is creating the file
> task_0001_m_000123_4 -> starts and fails because attempt 0 is creating the file
> job_0001 is killed because map_000123 failed 4 times. From this experience, I think we should change the scheduling so that:
>   1. Tasks are only allowed 1 speculative attempt.
>   2. TIPs don't kill jobs until they have 4 failures AND the last task under that tip fails.
> Thoughts?

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