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https://issues.apache.org/jira/browse/YARN-6319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15923881#comment-15923881
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Hong Zhiguo commented on YARN-6319:
-----------------------------------
The "app dir cleanup" is triggered in
ApplicationImpl.AppFinishTriggeredTransition or
ApplicationImpl.AppFinishTransition. There's pre-condition that all container
dirs are cleaned up.
{code}
if (app.containers.isEmpty()) {
// No container to cleanup. Cleanup app level resources.
app.handleAppFinishWithContainersCleanedup();
return ApplicationState.APPLICATION_RESOURCES_CLEANINGUP;
}
{code}
But this doesn't work. Because in
ResourceLocalizationService.handleCleanupContainerResources, only async
"container dir cleanup" is triggered, and then CONTAINER_RESOURCES_CLEANEDUP
event is sent out, which then leads to ApplicationImpl.AppFinishTransition and
ApplicationImpl.containers.Remove(...). So ApplicationImpl.containers could be
empty but "container dir cleanup" is still in fly.
> race condition between deleting app dir and deleting container dir
> ------------------------------------------------------------------
>
> Key: YARN-6319
> URL: https://issues.apache.org/jira/browse/YARN-6319
> Project: Hadoop YARN
> Issue Type: Bug
> Components: nodemanager
> Reporter: Hong Zhiguo
> Assignee: Hong Zhiguo
>
> Last container (on one node) of one app complete
> | --> triggers async deletion of container dir (container cleanup)
> | --> triggers async deletion of app dir (app cleanup)
> For LCE, deletion is done by container-executor. The "app cleanup" lists
> sub-dir (step 1), and then unlink items one by one(step 2). If a file is
> deleted by "container cleanup" between step 1 and step2, it'll report below
> error and breaks the deletion.
> {code}
> ContainerExecutor: Couldn't delete file
> $LOCAL/usercache/$USER/appcache/application_1481785469354_353539/container_1481785469354_353539_01_000028/$FILE
> - No such file or directory
> {code}
> This app dir then escape the cleanup. And that's why we always have many app
> dirs left there.
> solution 1: just ignore the error without breaking in
> container-executor.c::delete_path()
> solution 2: use a lock to serialize the cleanup of same app dir.
> solution 3: backoff and retry on error
> Comments are welcome.
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