Description of problem:

Customer wants to have a Compute node as a reserved one to use it only in case Instance HA is triggered. Evacuated instances should go to only on this reserved node.

Additional Info :

As per customer, Openstack community version Masakari service provides the high availability by using a feature called Reserve host recovery method which reserves the host in case of failover. Hence feasibility to have the same feature in our product is expected and required at the moment.
https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/ussuri/app-masakari.html
 
https://specs.openstack.org/openstack/masakari-specs/specs/ocata/implemented/implement-reserved-host-action.html

https://bugzilla.redhat.com/show_bug.cgi?id=2203124