Simulates an upgrade from a nova based undercloud to ironic provisioned servers.
Create the initial stack with one nova server:
openstack stack create --wait -e env-init.yaml -t stack.yaml provision-upgrade
Set deletion_policy: retain on the server:
openstack stack update --wait -e env-pre.yaml -t stack.yaml provision-upgrade
Upgrade to a pre-provisioned server without deleting the nova server:
openstack stack update --wait -e env-upgrade.yaml -t stack.yaml provision-upgrade