Raft's Leader Election Protocol

Leader election

All servers start as followers in Raft. A server keeps this state as long as it receives valid heartbeat RPCs (AppendEntries RPCs with no log entries) from the leader, which the leader uses to ascertain its authority. As soon as a follower stops receiving these heartbeat RPCs for a specific time duration, known as election timeout, it assumes that there is no valid leader currently. It changes its state to a candidate, starting a new election. ...