Its not a fair comparison to compare to k8s.

I've replaced pets with ASGs that do nothing but sit there unless the EC2 instance fails. Its amazing because you no longer have to baby the pet, it just recovers in a nice clean state, same massive instance..

Pets are a artifact of laziness.

It should still not be administered as a pet. In fact, it's even more important when you have a single instance of some importance to make it entirely rebuildable and replaceable.

A cattle server needs no special maintenance. Yes, if you only have one server then by definition it'll require special maintenance, but that maintenance should be as generic as practicable so that if you ever need to set up a second one then you don't need to do anything special. That's the distinction between pets and cattle, not the tooling: you can configure cattle by hand if you have a repeatable and non-special cased setup script to follow, and you can use Ansible or Puppet or whatever to set up the unique environment your pet server needs. The important thing is that the setup process, maintenance, etc is standardized and documented. Automated is a bonus that should be relatively easy if you're doing it right

Do you mean bare metal?