Jie Yu created MESOS-3178:
-----------------------------
Summary: 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
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 reply 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
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
