[prmoustache]

I am not saying docker is the best way to run any app, but could you share a kind of app can't you host in a docker?

I mean on rootless containers, yes, a lot of apps that need access to the underlying system might not work, but they are usually system stuff, not the kind you want to host on a VPS anyway. But when running as root I can't think of many.

[johnklos]

There are many, many things that can't be hosted in Docker. For instance, literally everything that I run on many of my servers can't, because Docker only supports certain platforms and architectures. Things that we want to run on systems with modest amounts of CPU and memory can't be run via Docker for obvious reasons. Stuff that needs hardware access can't. Stuff that needs finer resolution of permissions can, but there's a lot more work that needs to be done.

But even ignoring those, if I'm going to spend all the time needed to containerize everything in to Docker images myself, why wouldn't I just run the programs directly and not deal with the overhead and extra work?