Open source Java implementation for Raft consensus protocol.

Clone this repo:
  1. 5ee32b5 RATIS-1185. Avoid directly using RaftServerProxy in JvmPauseMonitor. (#304) by Tsz-Wo Nicholas Sze · 14 hours ago master
  2. c3a1d56 RATIS-1184. Move RaftServerMetrics to org.apache.ratis.server.metrics. (#303) by Tsz-Wo Nicholas Sze · 2 days ago
  3. e61333d RATIS-1183. Add getId() and getPeer() to RaftServer/RaftServer.Division. (#302) by Tsz-Wo Nicholas Sze · 3 days ago
  4. bcc392c RATIS-1161. Updating commit index of follower does not require term check (#289) by Tsz-Wo Nicholas Sze · 3 days ago
  5. bc9d761 RATIS-1182. Move RaftServerProxy/RaftServerImpl LOG to RaftServer. (#301) by Tsz-Wo Nicholas Sze · 3 days ago

Apache Ratis

Apache Ratis is a Java library that implements the Raft protocol [1], where an extended version of the Raft paper is available at The paper introduces Raft and states its motivations in following words:

Raft is a consensus algorithm for managing a replicated log. It produces a result equivalent to (multi-)Paxos, and it is as efficient as Paxos, but its structure is different from Paxos; this makes Raft more understandable than Paxos and also provides a better foundation for building practical systems.

Ratis aims to make Raft available as a java library that can be used by any system that needs to use a replicated log. It provides pluggability for state machine implementations to manage replicated states. It also provides pluggability for Raft log, and rpc implementations to make it easy for integration with other projects. Another important goal is to support high throughput data ingest so that it can be used for more general data replication use cases.


  1. Diego Ongaro and John Ousterhout, In Search of an Understandable Consensus Algorithm, 2014 USENIX Annual Technical Conference (USENIX ATC 14) (Philadelphia, PA), USENIX Association, 2014, pp. 305-319.