I was lucky enough to take David Beazley's "Rafting Trip," a five-day training course that guides each student through building their own Raft implementation from scratch:

https://www.dabeaz.com/raft.html

I'd recommend the course to anyone with development experience working with or near distributed systems. David is a fantastic instructor and facilitator, and the blend of student backgrounds led to some great learning and discussion.

(I have no financial or personal interest here; I just loved the course.)