Comment 6 for bug 1461459

I think the DocImpact in the nova change was probably just to get the config options docs updated with the new workaround option.

If there is anything else we could do with this, it could be to note in the docs related to evacuate operations that if you're running nova < liberty, there is a potential data loss issue with the evacuate functionality if you don't have that patch and don't set the option appropriately.

For example:

http://docs.openstack.org/user-guide-admin/cli_nova_evacuate.html

http://docs.openstack.org/admin-guide-cloud/compute-node-down.html

There was a spec in liberty to make this smarter, but the existing problem description applies to nova compute nodes < liberty:

http://specs.openstack.org/openstack/nova-specs/specs/liberty/implemented/robustify_evacuate.html#problem-description

If the hostname changes on the compute or you have a typo in your configs (multiple compute nodes managing the same vcenter running at the same time), that evacuate code can delete your instances.

That's why the workarounds.destroy_after_evacuate=False option is a way to safely get around this until you're sure that you're cleaning up a failed compute node (a real evacuation rather than a misconfiguration or hostname change), until you get your computes to liberty+.