Rebooting Ubuntu is hard. I don’t really know why, but in my twelve years as an Ubuntu user, I’ve encountered countless “stuck at reboot” scenarios. Somehow, typing reboot always comes with that extra special feeling of uncertainty and the thrill of danger. This post describes the short story of how we managed to make Ubuntu machines reliably reboot using Linux watchdogs.
Have you ever looked at the backplane of a server? You know, the kind that’s meant to go into a rack in a datacenter? They’ll usually have more than one ethernet port, but oddly, a lot of the time one of those ethernet ports is gonna be off to the side, over with the USB ports. That’s your server’s IPMI interface, and it can do a lot. We go over how to inspect and tear apart an IPMI image to learn how they're put together.