[jira] [Created] (MESOS-5856) Logrotate ContainerLogger module does not rotate logs when run as root with --switch_user

["Joseph Wu (JIRA)" <ji...@apache.org>]

Joseph Wu created MESOS-5856:
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             Summary: Logrotate ContainerLogger module does not rotate logs when run as root with --switch_user
                 Key: MESOS-5856
                 URL: https://issues.apache.org/jira/browse/MESOS-5856
             Project: Mesos
          Issue Type: Bug
    Affects Versions: 0.28.0, 0.27.0, 1.0.0
            Reporter: Joseph Wu
            Priority: Minor


The logrotate ContainerLogger module runs as the agent's user.  In most cases, this is {{root}}.

When {{logrotate}} is run as root, there is an additional check the configuration files must pass (because a root {{logrotate}} needs to be secured against non-root modifications to the configuration):
https://github.com/logrotate/logrotate/blob/fe80cb51a2571ca35b1a7c8ba0695db5a68feaba/config.c#L807-L815

Log rotation will fail under the following scenario:
1) The agent is run with {{--switch_user}} (default: true)
2) A task is launched with a non-root user specified
3) The logrotate module spawns a few companion processes (as root) and this creates the {{stdout}}, {{stderr}}, {{stdout.logrotate.conf}}, and {{stderr.logrotate.conf}} files (as root).  This step races with the next step.
4) The Mesos containerizer will {{chown}} the task's sandbox to the non-root user.  Including the files just created.
5) When {{logrotate}} is run, it will skip any non-root configuration files.  This means the files are not rotated.

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Fix: The logrotate module's companion processes should call {{setuid}} and {{setgid}}.



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