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https://issues.apache.org/jira/browse/YARN-8706?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16595851#comment-16595851
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Eric Yang commented on YARN-8706:
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{quote}But then we have redundant configs for no reason. And we would be
favoring the grace period config which only gives the granularity of seconds.
It also means that we have different treatment of a container getting killed
between runtimes, when we have the opportunity to maintain the same overall
design (except for privileged containers){quote}
I agree that the config are redundant and it is probably preferred to remove
NM_DOCKER_STOP_GRACE_PERIOD. I am not entirely sure about globally identical
killing mechanism for all container type, is a sane approach to brute force
container shutdown. There might be hidden danger that has not been discovered.
10 seconds default is probably more sensible to give container a chance to
shutdown gracefully without causing corruption to data.
> 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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