rafting

Raft library implemented in Java, easy to understand

• Complete features including AppendEntires, RequestVote, InstallSnapshot and PreVote
• Design focuses on understanding
• Asynchronous lock-free implementation using EventLoop
• Multi-Raft is supported

Architecture

According to the paper:

• Nodes communicate with RPC RaftService. So we provide an Event-Based async RPC Framework based on Netty and Kyro in io.lubricant.consensus.raft.transport.

• Basic operation Leader Election, Log Replication and Snapshot Synchronization are included in io.lubricant.consensus.raft.context. Besides, we define RaftContext concept to isolate irrelevant state machine and provide better concurrency.

• For reliable log persistence, we provide RaftLog which storage its entries in RocksDB.

• RSM model could adapt to various application by change its SateMachine. So we provide RaftMachine interface, and developer could crate unique Raft application by customizing their own RaftMachine.

• PreVote and InstallSnapshot are optional for developers and could be disabled

Correctness verification

To show the function of this lib, we simply implement a RaftMachine which only append the data on a file.

Run these 3 main class TestNode1~3 to setup a cluster then try to stop and restart these processes.

If system is functional, all 3 files should be consistent.