[cstuder]

Any recommendations for an uncomplicated server OS which will just run Docker, SSH and not much more?

I'm currently running Ubuntu but am open to alternatives. My local Raspberry Pi uses a fun, but little maintained OS called Hypriot which is just this: Start Docker and not much more.

[regularfry]

Just stick Debian on it. It'll be familiar enough from your Ubuntu experience, and if all you're going to do is slap Docker on it and run everything in containers you can just use Debian Stable, not care that things in the repo might not be bang up to date, stick unattended-upgrades on it, and never really worry about it until dist-upgrade time.

[layer8]

Seconding this.

[yrro]

RHEL, Debian.

If you're serious about running _everything_ in containers, then maybe RHEL Edge? RHEL + microshift? Fedora Silverblue? openSUSE MicroOS?

[e12e]

You probably want podman, not Docker, on RedHat (and SuSe).

[subsequentmask]

I'm quite a large fan of Debian, it's my go to choice for anything server personally. It's pretty good for what you want here IMHO, it's stable so you won't really have to worry about packages screwing you over and like another comment said you can stick unattended-upgrades on it :)

[NortySpock]

Dietpi is what I switched to.

Maintained, light on logging unless you ask for it (saves your SD card from wear and tear), and focused on low host-os resource usage while still being Debian-based.

[chpatrick]

Ubuntu is fine for that use case.