You're still free to do that. But honestly having done DevOps/sysadmin in both of those worlds, i vastly prefer the whole one-service-per-machine, cattle treatment with the one off exception for remote workspaces and the like.
Losing a server was often devastating, even with backups. "Don't run your builds right now, people are visiting the website" also sounds a lot like "Don't connect to the internet right now, i need to use the phone".
I mean there's "correct" ways to implement the whole pet servers concept but .. why? It's fun, sure, but it's also a waste of time, and when you want to be productive it just tends to get in your way.
