Public bug reported: A data corruption bug exists in the LXC driver for libvirt, that has just cost me a MySQL server.
Steps to reproduce: - (for visualization only) In virt-manager add a connection to local lxc:// - create an LXC container, that has a loop-mounted image file and start it - (for visualization only) the container shows as running in virt-manager - systemctl stop libvirtd ; sleep 2 ; sync ; systemctl start libvirtd - (for visualization only) the container shows as shut off in virt-manager - The container no longer responds to network requests, has no attachable console - The loop mount does no longer show up on host-side "mount" output BUT: losetup -a reveals, that a loop device is still attached to the image file BUT: In reality this loop device is still mounted, processes in the container still access the file system BUT: There is no way to unmount or free it - losetup -d ends without an error but does nothing - restart the container (virsh -c lxc:// start name-of-container or via virt-manager) THIS SHOULD NOT BE ALLOWED - The image file is now twice mounted and corruption starts creeping in - Depending on how long this state persists (in terms of IO), the damage can be significant When finally discovering the problem, the only way to unstick the container is a reboot. This is the final nail in the coffin: The hidden instance syncs AFTER the new instance, effectivly pushing back the past. This can be quite nasty, if a libvirt restart results from an unattended upgrade. I do understand, that libvirt/LXC is deprecated - this strikes me as a rather unsubtle way to push users to the newest incarnation, though. In non-enterprisy environments (read SMB or NGO) virt-manager is often used as a "power user" tool, and those end users are unwilling if not unable to use different toolsets for containers and full-fledged VMs. And disabling unattended upgrades in such an environment is inviting trouble. ** Affects: libvirt (Ubuntu) Importance: Undecided Status: New ** Package changed: udev (Ubuntu) => libvirt (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1680997 Title: Container file system corruption on libvirtd restart To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1680997/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs