Dokuwiki (dokuwiki.org) is my usual go-to. It’s really simple and stores entries in markdown files so you can get at them as plain text files in a pinch. Here’s a life lesson: don’t host your documentation in the machine you’re going to be breaking! Learned that the hard way once or twice.

For reverse proxies, I’m a fan of HAProxy. It uses pretty straightforward config files and is incredibly robust.