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https://issues.apache.org/jira/browse/YARN-8382?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16499324#comment-16499324
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Hu Ziqian commented on YARN-8382:
---------------------------------
[~miklos.szeg...@cloudera.com], I added a new patch which set cgroup delete
delay to sigkill timeout + 1 second + NM_LINUX_CONTAINER_CGROUPS_DELETE_TIMEOUT
and fixed the checkstyle.
> cgroup file leak in NM
> ----------------------
>
> Key: YARN-8382
> URL: https://issues.apache.org/jira/browse/YARN-8382
> Project: Hadoop YARN
> Issue Type: Bug
> Components: nodemanager
> Environment: we write an container with a shutdownHook which has a
> piece of code like "while(true) sleep(100)" . when
> *yarn.nodemanager.linux-container-executor.cgroups.delete-timeout-ms <*
> *yarn.nodemanager.sleep-delay-before-sigkill.ms , cgourp file leak happens;
> when* *yarn.nodemanager.linux-container-executor.cgroups.delete-timeout-ms >*
> ** *yarn.nodemanager.sleep-delay-before-sigkill.ms, cgroup file is deleted
> successfully***
> Reporter: Hu Ziqian
> Assignee: Hu Ziqian
> Priority: Major
> Attachments: YARN-8382-branch-2.8.3.001.patch,
> YARN-8382-branch-2.8.3.002.patch, YARN-8382.001.patch, YARN-8382.002.patch
>
>
> As Jiandan said in YARN-6525, NM may delete Cgroup container file timeout
> with logs like below:
> org.apache.hadoop.yarn.server.nodemanager.util.CgroupsLCEResourcesHandler:
> Unable to delete cgroup at: /cgroup/cpu/hadoop-yarn/container_xxx, tried to
> delete for 1000ms
>
> we found one situation is that when we set
> *yarn.nodemanager.sleep-delay-before-sigkill.ms* bigger than
> *yarn.nodemanager.linux-container-executor.cgroups.delete-timeout-ms*, the
> cgroup file leak happens *.*
>
> One container process tree looks like follow graph:
> bash(16097)───java(16099)─┬─\{java}(16100)
> ├─\{java}(16101)
> {{ ├─\{java}(16102)}}
>
> {{when NM kills a container, NM sends kill -15 -pid to kill container process
> group. Bash process will exit when it received sigterm, but java process may
> do some job (shutdownHook etc.), and doesn't exit unit receive sigkill. And
> when bash process exits, CgroupsLCEResourcesHandler begin to try to delete
> cgroup files. So when
> *yarn.nodemanager.linux-container-executor.cgroups.delete-timeout-ms*
> arrived, the java processes may still running and cgourp/tasks still not
> empty and cause a cgroup file leak.}}
>
> {{we add a condition that
> *yarn.nodemanager.linux-container-executor.cgroups.delete-timeout-ms* must
> bigger than *yarn.nodemanager.sleep-delay-before-sigkill.ms* to solve this
> problem.}}
>
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