That's the weird part. It's trivially simple to run a Minecraft server. Slap whatever your favorite variant of Linux is, install Java, run minecraft-server.jar. Make a service for it (heck I made one many years ago, probably still works: https://gist.github.com/chungy/0b2c438c7db90b32701a).
Once you have the Raspberry Pis, pre-installing an operating system to run the standard Minecraft server should be the easy part.
Unless, of course, it really was a case of "reverse engineer and reimplement Minecraft to make my own server." Not strictly impossible, but a completely unreasonable goal.
Once you have the Raspberry Pis, pre-installing an operating system to run the standard Minecraft server should be the easy part.
Unless, of course, it really was a case of "reverse engineer and reimplement Minecraft to make my own server." Not strictly impossible, but a completely unreasonable goal.