Raft consensus algorithm
The Raft consensus algorithm provides a way to elect a leader for a distributed cluster from a pool of potential leaders. If a follower cannot reach the current leader, it transitions itself to become a candidate. Given a quorum of voters, one candidate is elected to be the new leader, and the others transition back to being followers.
A full discussion of Raft is out of scope for this documentation, but it is a robust algorithm.
Kudu uses the Raft consensus algorithm for the election of masters and leader tablets, as well as determining the success or failure of a given write operation.