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Posted to mapreduce-issues@hadoop.apache.org by "Peter Bacsko (JIRA)" <ji...@apache.org> on 2017/12/01 15:19:01 UTC
[jira] [Commented] (MAPREDUCE-7015) Possible race condition in JHS
if the job is not loaded
[ https://issues.apache.org/jira/browse/MAPREDUCE-7015?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16274505#comment-16274505 ]
Peter Bacsko commented on MAPREDUCE-7015:
-----------------------------------------
Uploaded a POC for this - I think making the call to {{moveToDone()}} solves the problem, although I can't tell whether it can affect the performance negatively.
> Possible race condition in JHS if the job is not loaded
> -------------------------------------------------------
>
> Key: MAPREDUCE-7015
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7015
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobhistoryserver
> Reporter: Peter Bacsko
> Assignee: Peter Bacsko
> Attachments: MAPREDUCE-7015-POC01.patch
>
>
> There could be a race condition inside JHS. In our build environment, {{TestMRJobClient.testJobClient()}} failed with this exception:
> {noformat}
> ava.io.FileNotFoundException: File does not exist: hdfs://localhost:32836/tmp/hadoop-yarn/staging/history/done_intermediate/jenkins/job_1509975084722_0001_conf.xml
> at org.apache.hadoop.hdfs.DistributedFileSystem$20.doCall(DistributedFileSystem.java:1266)
> at org.apache.hadoop.hdfs.DistributedFileSystem$20.doCall(DistributedFileSystem.java:1258)
> at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
> at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1258)
> at org.apache.hadoop.fs.FileUtil.copy(FileUtil.java:340)
> at org.apache.hadoop.fs.FileUtil.copy(FileUtil.java:292)
> at org.apache.hadoop.fs.FileSystem.copyToLocalFile(FileSystem.java:2123)
> at org.apache.hadoop.fs.FileSystem.copyToLocalFile(FileSystem.java:2092)
> at org.apache.hadoop.fs.FileSystem.copyToLocalFile(FileSystem.java:2068)
> at org.apache.hadoop.mapreduce.tools.CLI.run(CLI.java:460)
> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
> at org.apache.hadoop.mapreduce.TestMRJobClient.runTool(TestMRJobClient.java:94)
> at org.apache.hadoop.mapreduce.TestMRJobClient.testConfig(TestMRJobClient.java:551)
> at org.apache.hadoop.mapreduce.TestMRJobClient.testJobClient(TestMRJobClient.java:167)
> {noformat}
> Root cause:
> 1. MapReduce job completes
> 2. CLI calls {{cluster.getJob(jobid)}}
> 3. The job is finished and the client side gets redirected to JHS
> 4. The job data is missing from {{CachedHistoryStorage}} so JHS tries to find the job
> 5. First it scans the intermediate directory and finds the job
> 6. The call {{moveToDone()}} is scheduled for execution on a separate thread inside {{moveToDoneExecutor}} but does not get the chance to run immediately
> 7. RPC invocation returns with the path pointing to {{/tmp/hadoop-yarn/staging/history/done_intermediate}}
> 8. The call to {{moveToDone()}} completes which moves the contents of {{done_intermediate}} to {{done}}
> 9. Hadoop CLI tries to download the config file from done_intermediate but it's no longer there
> Usually step #6 is fast enough to complete before step #7, but sometimes it can get behind, causing this race condition.
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