PiKVM - a KVM <-> IP on System76

Is always better to have a Plan B if the main plan fails.
My server has an embedded KVM (with an extra module installed - see the article Fixing the server - KVM <-> IP) but surprise surprise the actual KVM functionality is not working because the motherboard is not supporting an extension module.

This article discuss about the KVM <-> IP solution with a Raspberry Pi on the open source project PiKVM as a way to have the KVM functionality on my server.

Server chronicles - KVM <-> IP on old System76

One of the things I would like to have in the renewed server is the capability to remote access it for monitor or emergency repairs or, like now, for a rebuilding, without the need to be physically present in the "server room" (in my case the garage) to connect a keyboard and monitor to the console.
This article is about the introduction and hardware settings, another one will discuss the installation and use.