Document additional required host binaries

k0sproject / k0s

k0s - The Zero Friction Kubernetes

https://docs.k0sproject.io

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Document additional required host binaries #3841

Open twz123 opened 7 months ago

twz123 commented 7 months ago

K0s actually requires quite some host binaries to be present on worker machines. The docs should reflect that, and maybe some sysprobes should be added. See https://github.com/k0sproject/k0s/issues/3386#issuecomment-1864203357 for details:

Looking at the repo https://github.com/kubernetes/mount-utils where all mount stuff is implemented, replacing (u)mount calls with syscalls is only small part of the problem. There's plenty of other exec calls it does to resize FS, systemd dependencies, FS initialization etc.. Replacing all these is really not feasible or possible. So replacing just mount doesn't really get us anywhere IMO. xref: https://github.com/kubernetes/mount-utils/issues/13

jnummelin commented 7 months ago

I think the challenge, especially relating to the mount-utils, is that not all the host bins are always needed. I think some of the exec calls are still due to in-tree volume providers and thus not always really needed. But in general I agree, we need to document these at least as soft dependencies.

twz123 commented 7 months ago

We already check quite some optional things in the sysprobes, e.g. some kernel config options. No need to have them to be hard failures, nevertheless good to know if they're missing.