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https://issues.apache.org/jira/browse/YARN-8706?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16595507#comment-16595507
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Shane Kumpf commented on YARN-8706:
-----------------------------------
Thanks for reporting this, [~csingh]. I know several of us discussed this in
the past and ran into some sticking points.
As [~ebadger] points out, the reason for using {{docker stop}} is to be able to
leverage the STOPSIGNAL directive that can be used in Dockerfiles. {{docker
stop}} will issue the signal defined in the STOPSIGNAL instead of SIGTERM. This
is important for gracefully stopping databases and even systemd (which expects
SIGRTMIN+3).
> DelayedProcessKiller is executed for Docker containers even though docker
> stop sends a KILL signal after the specified grace period
> -----------------------------------------------------------------------------------------------------------------------------------
>
> Key: YARN-8706
> URL: https://issues.apache.org/jira/browse/YARN-8706
> Project: Hadoop YARN
> Issue Type: Sub-task
> Reporter: Chandni Singh
> Assignee: Chandni Singh
> Priority: Major
> Labels: docker
>
> {{DockerStopCommand}} adds a grace period of 10 seconds.
> 10 seconds is also the default grace time use by docker stop
> [https://docs.docker.com/engine/reference/commandline/stop/]
> Documentation of the docker stop:
> {quote}the main process inside the container will receive {{SIGTERM}}, and
> after a grace period, {{SIGKILL}}.
> {quote}
> There is a {{DelayedProcessKiller}} in {{ContainerExcecutor}} which executes
> for all containers after a delay when {{sleepDelayBeforeSigKill>0}}. By
> default this is set to {{250 milliseconds}} and so irrespective of the
> container type, it will always get executed.
>
> For a docker container, {{docker stop}} takes care of sending a {{SIGKILL}}
> after the grace period
> - when sleepDelayBeforeSigKill > 10 seconds, then there is no point of
> executing DelayedProcessKiller
> - when sleepDelayBeforeSigKill < 1 second, then the grace period should be
> the smallest value, which is 1 second, because anyways we are forcing kill
> after 250 ms
>
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