[jira] [Commented] (YARN-6319) race condition between deleting app dir and deleting container dir

["Hong Zhiguo (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/YARN-6319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15906816#comment-15906816 ] 

Hong Zhiguo commented on YARN-6319:
-----------------------------------

The race condition could be reproduced by below script:
{code}
USER=xxx
GRP=yyy
CE=/PATH/TO/container-executor
SIZE=200

mkdir app
mkdir -p app/container
dd if=/dev/zero of=app/container/a count=$SIZE bs=1M
dd if=/dev/zero of=app/container/b count=$SIZE bs=1M
dd if=/dev/zero of=app/container/c count=$SIZE bs=1M
dd if=/dev/zero of=app/container/d count=$SIZE bs=1M
dd if=/dev/zero of=app/container/e count=$SIZE bs=1M
chown $USER:$GRP -R app/

$CE $USER 3 ./app/container &
$CE $USER 3 ./app
{code}


> 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
> Suggestions are welcome.



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