[Bug 1832859] Re: during shutdown libvirt-guests gets stopped after file system unmount

[Christian Ehrhardt ]

It seems - somewhat expected - that the solution needs to be a bit
bigger due to further service dependencies that might create a loop.
Until that solution is sorted out upstream we should not implement
another custom emergency fix that might cause more trouble.

Instead while we wait on the final solution by upstream I'd recommend
that everybody affected needs to evaluate his own system if the
modification suggested in comment #8 would suffice as a workaround for
you.

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Title:
  during shutdown libvirt-guests gets stopped after file system unmount

Status in lvm2:
  New
Status in libvirt package in Ubuntu:
  Incomplete
Status in lvm2 package in Ubuntu:
  New
Status in lvm2 package in Fedora:
  Unknown

Bug description:
  When using automatic suspend at reboot/shutdown, it makes sense to
  store the suspend data on a separate partition to ensure there is
  always enough available space. However this does not work, as the
  partition gets unmounted before or during libvirt suspend.

  Steps to reproduce:

  1. Use Ubuntu 18.04.02 LTS
  2. Install libvirt + qemu-kvm
  3. Start a guest
  4. Set libvirt-guests to suspend at shutdown/reboot by editing /etc/default/libvirt-guests
  5. Create a fstab entry to mount a separate partition to mount point /var/lib/libvirt/qemu/save. Then run sudo mount /var/lib/libvirt/qemu/save to mount the partition.
  6. Reboot

  Expected result:
  The guest suspend data would be written to the /var/lib/libvirt/qemu/save, resulting in the data being stored at the partition specified in fstab. At boot, this partition would be mounted as specified in fstab and libvirt-guest would be able to read the data and restore the guests.

  Actual result:
  The partition gets unmounted before libvirt-guests suspends the guests, resulting in the data being stored on the partition containing the root file system. During boot, the empty partition gets mounted over the non-empty /var/lib/libvirt/qemu/save directory, resulting in libvirt-guests being unable to read the saved data.

  As a side effect, the saved data is using up space on the root
  partition even if the directory appears empty.

  Here is some of the relevant lines from the journal:

  Jun 14 00:00:04 libvirt-host blkdeactivate[4343]: Deactivating block devices:
  Jun 14 00:00:04 libvirt-host systemd[1]: Unmounted /var/lib/libvirt/qemu/save.
  Jun 14 00:00:04 libvirt-host blkdeactivate[4343]:   [UMOUNT]: unmounting libvirt_lvm-suspenddata (dm-3) mounted on /var/lib/libvirt/qemu/save... done

  Jun 14 00:00:04 libvirt-host libvirt-guests.sh[4349]: Running guests on default URI: vps1, vps2, vps3
  Jun 14 00:00:04 libvirt-host blkdeactivate[4343]:   [MD]: deactivating raid1 device md1... done
  Jun 14 00:00:05 libvirt-host libvirt-guests.sh[4349]: Suspending guests on default URI...
  Jun 14 00:00:05 libvirt-host libvirt-guests.sh[4349]: Suspending vps1: ...
  Jun 14 00:00:05 libvirt-host blkdeactivate[4343]:   [LVM]: deactivating Volume Group libvirt_lvm... skipping

  Jun 14 00:00:10 libvirt-host libvirt-guests.sh[4349]: Suspending vps1: 5.989 GiB
  Jun 14 00:00:15 libvirt-host libvirt-guests.sh[4349]: Suspending vps1: ...
  Jun 14 00:00:20 libvirt-host libvirt-guests.sh[4349]: Suspending vps1: ...

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