Learning how to do all of this is laudable for the same reason that learning LinuxFromScratch is a stupendous way to learn how Linux works and to get a job doin

Learning how to do all of this is laudable for the same reason that learning LinuxFromScratch is a stupendous way to learn how Linux works and to get a job doing lower level maintenance work. That said, everything on your list is provided out of the box with managed cloud vendors like AWS's Aurora DB clusters. Replica lag: check. Primary and replica status checks: check. Auto-failover with strategies: check. Split brain: I'll be honest, this is a deceptively hard problem that is strongly dependent on use cases and setting expectations. CAP theorem exists for a reason. Do NOT trust anyone who tells you they have a one and done solution to this. They're selling snake oil. After failover recovery: check. ---- Please note that I recognize you want to learn this for yourself, and I wholeheartedly encourage you to. I think it's important to know that there are already mature solutions out there that trade money in exchange for your time to be spent in other areas.