Maybe we can pile on that feature request. I never feel like those are taken seriously, but if enough of us ask maybe they'll implement. But I have to guess that they coded themselves into a corner, because unregistering comes with all sorts of required conditions. Almost like they don't know how to unregister a server that was built in vRA (as opposed to onboarded) or one that not longer meets one of those conditions. But I think the entire community would love the ability to simply unregister any server resource at any time. I don't understand how they don't know how to clean those things up on their side.
In the meantime, if deleting the server is viable, we use a custom propery that contains "build" flags. So for example during the build, if we successfully create a dns record, we turn the dns flag on. Then when the "destroy" subs kick in, we check those flags before taking action. So for example, if we never created a dns record and the build failed, we don't try to remove it.
With that in mind, we have a day-2 to allow users to delete a deployment without removing records from DNS, AD, etc. It simply flips all of those flags to false via the api, then issues a delete on the deployment. When it somes to those "destroy" subs, the flag is off and we therefore don't delete from DNS, AD, etc. So the server ends up deleted but all of the other pieces remain. Not sure if that's helpful for anyone, but wanted to mention it.
