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https://issues.apache.org/jira/browse/MAPREDUCE-4819?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Joseph Evans updated MAPREDUCE-4819:
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Attachment: MR-4819-bobby-trunk.txt
This patch should be fully functional.
I have included the work by Bikas to put the Job history file in a location
that is deleted with the staging directory. I have fixed a few bugs in the
original where we were not registering with the RM correctly. And also where
the Web App Proxy would return a 500 error if hit when recovery was happening.
I have manually tested this by having the AM exit/halt before, during, and
after job commit. I tested it with the job commit failing and succeeding.
Everything appears to be working as expected.
I did not change JobImpl forcedState because adding in the transitions was more
then I wanted to do right now. I am happy to file a follow up JIRA to make
those changes if we want them.
I have also not added in the kill state. Again it looked a bit tricky because
of the multithreading and I would prefer to get something working in now and
add that as part of a follow up JIRA.
I talked with Kihwal Lee about the extra HDFS load for an empty file vs a
directory and he said about the only extra load is the extra PRC call to close
it, and because it is just two files per job I left it as is. If you feel
strongly about it I can fix it on a separate JIRA.
About the only thing that is left for this is integration with MAPREDUCE-4832.
> AM can rerun job after reporting final job status to the client
> ---------------------------------------------------------------
>
> Key: MAPREDUCE-4819
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4819
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mr-am
> Affects Versions: 0.23.3, 2.0.1-alpha
> Reporter: Jason Lowe
> Assignee: Bikas Saha
> Priority: Critical
> Attachments: MAPREDUCE-4819.1.patch, MAPREDUCE-4819.2.patch,
> MAPREDUCE-4819.3.patch, MR-4819-bobby-trunk.txt, MR-4819-bobby-trunk.txt,
> MR-4819-bobby-trunk.txt
>
>
> If the AM reports final job status to the client but then crashes before
> unregistering with the RM then the RM can run another AM attempt. Currently
> AM re-attempts assume that the previous attempts did not reach a final job
> state, and that causes the job to rerun (from scratch, if the output format
> doesn't support recovery).
> Re-running the job when we've already told the client the final status of the
> job is bad for a number of reasons. If the job failed, it's confusing at
> best since the client was already told the job failed but the subsequent
> attempt could succeed. If the job succeeded there could be data loss, as a
> subsequent job launched by the client tries to consume the job's output as
> input just as the re-attempt starts removing output files in preparation for
> the output commit.
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