Comment 0 for bug 1530860

When running an instance from an image in a Cinder Quobyte volume issues arise when the corresponding Nova service (openstack-nova-compute) is restarted or stopped while the instance is active. systemd sigterms the whole cgroup, this includes the Quobyte client(s) handling the instances mount point(s), which effectively removes the image from under the VM(s).

Possible immediate Mitigation steps:
- Do _NOT_ restart/stop a Nova service that has running instances using images in Cinder Quobyte volumes
- Reconfigure sytemd.kill to use killmode=process or killmode=none instead of killmode=control-group (which is the default).
- Migrate instances off the host prior to restarting/stopping the Nova service.

The future solution will be to remove the client instance from the cgroup of the Nova Quobyte driver.