The sort of program that once set up, just ticks along without fuss or bother forever.
For me, as I’m replacing the vms today which I set up five years ago and haven’t needed to touch since;
- HAProxy
- KeepaliveD
Not easy to learn, but once they’re running, they both go on forever.
Prosody for me. I set it up over 2 years ago, and the only time I touched it was when updating to the latest Debian stable and enabling some new features in the config files. It’s been rock-solid and just worked without complaint.