Raft is a consensus algorithm designed to ensure fault-tolerance in distributed systems. It is used to maintain a replicated log that stores a sequence of state changes across multiple nodes in a cluster. Raft achieves consensus by electing a leader, which coordinates the communication among the nodes and ensures that the log is consistent across the cluster.

The Raft algorithm consists of three main components: leader election, log replication, and safety. In the leader election phase, nodes in the cluster elect a leader using a randomized timeout mechanism.

The leader then coordinates the log replication by receiving state changes from clients and replicating them across the nodes in the cluster. Nodes can also request entries from the leader to ensure consistency across the cluster.

The safety component of Raft ensures that the algorithm is resilient to failures and ensures that the log is consistent across the cluster. Raft achieves safety by ensuring that only one node can be the leader at any given time and by enforcing a strict ordering of log entries across the cluster.

Raft is widely used in distributed systems to provide fault-tolerance and high availability. It is often used in systems that require strong consistency guarantees, such as distributed databases and key-value stores.