When a compute host is rebooted, regardless of the reason, Nova is configured by default to leave all instances on that hypervisor in a shutoff state. If this behavior is considered undesirable, an optional Nova configuration option can be set on a per-host basis to automatically start guests that were running before the host rebooted.
- Platform9 Managed OpenStack - All Versions
- Nova (Compute Service)
Set the following on each host where this behavior is desired in the /opt/pf9/etc/nova/conf.d/nova_override.conf file.
[DEFAULT] resume_guests_state_on_host_boot = True
Restart the Compute service.
#systemctl restart pf9-ostackhost
On the next reboot of the hypervisor, nova will resume all the Virtual Machines once the pf9ostackhost service is up and running.
Warning: Use this configuration option with care, it is likely that all the VMs attempting to start will cause a boot storm anf it will cause problems if the underlying hypervisor does not have sufficient resources.