Raft
termcloudprogramming
A consensus algorithm designed to be understandable, giving the same guarantees as Paxos through an explicit leader, an append-only log and a defined election.
Its contribution is pedagogical and that is not a small thing: an algorithm that operators can reason about is one they configure correctly, and most consensus outages are configuration rather than mathematics. It separates the problem into leader election, log replication and safety, which also maps onto what a monitoring system can show you. If you run etcd, Consul or a modern distributed store, you are running this, and the practical rule that falls out is the familiar one - odd member counts, and a minority that stops.