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.
I set up a couple of pi-zeros to monitor our heating and other stuff, it runs lightpd and have been running for several years uninterrupted.
They are only accessible on the local network, so I don’t even bother to run updates :-)