[jira] [Assigned] (FLINK-6300) PID1 of docker images does not behave correctly

["Patrick Lucas (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-6300?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Patrick Lucas reassigned FLINK-6300:
------------------------------------

    Assignee: Patrick Lucas

> PID1 of docker images does not behave correctly
> -----------------------------------------------
>
>                 Key: FLINK-6300
>                 URL: https://issues.apache.org/jira/browse/FLINK-6300
>             Project: Flink
>          Issue Type: Bug
>          Components: Docker
>    Affects Versions: 2.0.0, 1.1.4
>         Environment: all
>            Reporter: kathleen sharp
>            Assignee: Patrick Lucas
>            Priority: Minor
>
> When running the task manager and job manager docker images the process with PID1 is a bash script.
> There is a problem in using bash as the PID1 process in a docker
> container as docker sends SIGTERM, but bash doesn't send this to its
> child processes.
> This means for example that if a container was ever killed and a child
> process had a file open then the file may get corrupted.
> It's covered in more detail in a blog post here:
> https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/
> From the mailing list (Nico):
> "Some background:
> Although docker-entrypoint.sh uses "exec" to run succeeding bash scripts for
> jobmanager.sh and taskmanager.sh, respectively, and thus replaces itself with
> these scripts, they do not seem to use exec themselves for foreground
> processes and thus may run into the problem you described.
> I may be wrong, but I did not find any other fallback to handle this in the
> current code base."
> Potentially useful information:
> dockerd version 1.1.3 added an init flag:
> "You can use the --init flag to indicate that an init process should be used as the PID 1 in the container. Specifying an init process ensures the usual responsibilities of an init system, such as reaping zombie processes, are performed inside the created container."
> from:
> https://docs.docker.com/engine/reference/run/#restart-policies---restart
> perhaps the fix could be just to update readme for these images to specify to use this flag.



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