[jira] [Updated] (MESOS-3178) Perform a self bind mount of rootfs itself in fs::chroot::enter.

["Jie Yu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/MESOS-3178?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jie Yu updated MESOS-3178:
--------------------------
    Fix Version/s: 0.24.0

> Perform a self bind mount of rootfs itself in fs::chroot::enter.
> ----------------------------------------------------------------
>
>                 Key: MESOS-3178
>                 URL: https://issues.apache.org/jira/browse/MESOS-3178
>             Project: Mesos
>          Issue Type: Bug
>            Reporter: Jie Yu
>            Assignee: Jie Yu
>             Fix For: 0.24.0
>
>
> Syscall 'pivot_root' requires that the old and the new root are not in the same filesystem. Otherwise, the user will receive a "Device or resource busy" error.
> Currently, we rely on the provisioner to prepare the rootfs and do proper bind mount if needed so that pivot_root can succeed. The drawback of this approach is that it potentially pollutes the host mount table which requires cleanup logics.
> For instance, in the test, we create a test rootfs by copying the host files. We need to do a self bind mount so that we can pivot_root on it. That pollute the host mount table and it might leak mounts if test crashes before we do the lazy umount:
> https://github.com/apache/mesos/blob/master/src/tests/containerizer/launch_tests.cpp#L96-L102
> What I propose is that we always perform a recursive self bind mount of rootfs itself in fs::chroot::enter (after enter the new mount namespace). Seems that this is also done in libcontainer:
> https://github.com/opencontainers/runc/blob/master/libcontainer/rootfs_linux.go#L402



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