Using an external Puppet Enterprise server is on my agenda. Note that is not running the installer, but using it at runtime. Ideally getting reports out of it. I’ve done some research and have some ideas, but this is the first step to making that possible. Foreman Proxy together with Puppet in docker container - #2 by ekohl has a slight preview in that direction.
We have users who do this manually. For Katello it’s currently not really supported for upgrades because a lot of logic is in the hooks, but I’m hoping we can make this easier in the future by removing those hooks. There’s also migrations and I don’t know how to deal with that. Currently it’s unsupported, but users who do this manually know how to read the CHANGELOGs and do it themselves.