A stand alone windows 2012 R2 essentials server was used to control a technical installation. Essentials was used (afaik) because of license reasons. The server is its own domain controller (and is an will ever be its own only member).
The operator of the installation now wants a spare Server. In case of failure the server would be completely exchanged with the spare server. Because there is no data that needs to be replicated, we thought that would be easy. Create an identical clone of the Server (they won't ever be online both at the same time, so even IP adress could be the same) and put it in the spare part storage.
A colleage of me told me, that this will not work. He wasn't sure about tombstone time if the controller is its own single member but he thought some certificates that the domain controller will generate from time to time will time out or something like that.
Is he right? What would happen if (after 1 or 2 years) the original server crashes and the 2 years ago cloned spare will be powered up?