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https://issues.apache.org/jira/browse/YARN-8706?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16596883#comment-16596883
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Eric Yang commented on YARN-8706:
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{quote}Why is this specific to docker containers? Other types of containers
maybe dealing with data and if the default grace period of 250 millis is too
small, then it can be changed with the config NM_SLEEP_DELAY_BEFORE_SIGKILL_MS.
Maybe this should be something that the application could specify as well, but
that is a different discussion.{quote}
YARN containers were mostly stateless, and not reused. The short termination
wait time can work without causing problem to Hadoop specific application.
With introduction of Docker container, it might take several seconds to
gracefully shutdown a database daemon. 10 seconds default seems like a safer
wait time if docker container is persisted and reused. There isn't much data
point to show waiting longer is better at this time. The default setting may
be revisited later.
> 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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