>I think rolling release distros are your friend for these type of all-in-one setups. Small weekly updates. Easy to test too because you only need one test machine.

I think the important thing here is a distro that tests it's changes well, and one that doesn't force you into a major upgrade (where you have to change your configs) very often.

Releases like Debian that want you to do a rolling major upgrade every two years, I think, are more difficult to deal with, because the major upgrades, if you have anything at all custom and the config file format changed, are going to require work and testing for you to move the configs over, even if the developers test perfectly (and nothing is perfect.)

I think RHEL/CentOS is best, assuming that the latest RHEL/CentOS supports all the packages in-distro. (If you need to step outside of the distro repos, that kind of defeats the point. maintaining a package yourself on an ancient distro gets old fast, and most of the smaller 3rd party repos don't put as much effort into keeping the old package versions patched up.)

That's the thing, sure, you have to format and re-install for a major upgrade, but you have ten years before you have to worry about that.