Raft is a consensus algorithm for building a replicated log.

It gives a group of servers one agreed order of commands, even when some servers crash, restart, or fall behind. Each server applies that same command sequence to its local state machine. If the state machine is deterministic, all servers end up with the same state.

Raft was designed to be easier to understand and implement than Paxos. It does this by using a strong leader, splitting the protocol into smaller pieces, and specifying the practical details that Paxos leaves open.

Systems such as etcd, Consul, CockroachDB, TiKV, Vault, and Kafka's KRaft metadata quorum use Raft or Raft-inspired protocols for critical replicated state.