Comment 7 for bug 1512908

This bug doesn't necessarily look actionable by landscape, the nova-compute charm restarts libvirt-bin on most config-changed hooks. Nova compute manager runs a number of periodic task which creates a new connection to libvirt and attempts to _set_host_enabled(). If the connection fails due to libvirt-bin service being down during a service restart, the compute manager tracesback and then stops working and the compute node never gets registered.

The fix would be for nova compute manager's periodic_tasks to be a bit more resilient of the libvirt connection fails.

One "workaround" in our charms would be to restart nova-compute services after any libvirt-bin restart to ensure the manager is recovered and operational in case there was a periodic_task collision.