[burnte]

A few years ago, we needed to move 4 VMs from one host in a DC nearby to on-prem. They were in their own little IP subnet, and they ran this crappy software called CoPath from Cerner. The app, being written in PowerBuilder, it was a delicate app, and I called up Cerner to ask the best way to move these VMs since we'd need to change the IP address space they occupied. Cerner said they had no idea what might happen, it might work, or everything might break. The safest path was to reinstall in new VMs and move the data. It would be $25,000 to do that. I laughed, said I can get a new LIS system for taht including data import. They said they'd take that feedback to the quote team, never got another response.

I changed LIS systems, saved money.

[skissane]

Some software I used to work on, had this sort of issue. Customers would call up and say "how do I change the machine's IP address" and Support would reply "you can't, you have to reinstall".

What was really going on: there were a whole bunch of config files, into several of which the installer embedded whatever was the machine IP at install time. Support didn't know exactly how many files there were. Engineering was asked to document them all but for whatever reason were dragging their feet on doing it. My attitude was – why can't we just do a search&replace? Response I got – we can't trust customers/Support to do that without making a mess of it.

Eventually, engineering wrote and shipped a "change machine IP tool" which knew about exactly which config files contained the machine IP. Finally, we had a supported procedure for changing the IP address of the server.