Public bug reported: I'm on Ubuntu 14.04.3 LTS, and recently upgraded to docker.io 1.6.2~dfsg1-1ubuntu4~14.04.1. This package provides the file /etc/init/docker.conf, which includes this:
pre-start script # Cleanup any stale mounts left from previous shutdown # see https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1404300 grep "mapper/docker" /proc/mounts | awk '{ print $2 }' | \ xargs -r umount || true end script My host's root filesystem is on an LVM volume named "docker1-root", and so /proc/mounts includes the line /dev/mapper/docker1-root / ext4 rw,relatime,errors=remount- ro,data=ordered 0 0 Thus running the docker.io pre-start script causes the root filesystem to be remounted read-only. ** Affects: docker.io (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1511784 Title: Starting docker.io remounts root filesystem read-only To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1511784/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs