I’m using that exact feature for a blue/green/another color deploy setup, it’s very nice. The server with the hosted application builds a vm of itself, run some checks. Route traffic to (RR). If it’s all good, send the VM to a secondary house and route to there. On the primary, reboot (usually kexec). Switch back over.

Should probably just be using a persistent but this is some pretty heterogenous hardware and…it works