raft-rs

A toy implementation to better understand the Raft consensus protocol

TODO:

• Fuzz test the protocol.
  • make timeout independent of tokio
• sim
  • unique server id
  • faster router
  • large size cluster test
• add len to packet header
• queues
  • ring buffer for queues
  • queue bounds check rather than overflow
  • fragmented packets (TCP can deliver a payload over multiple packets)
• network send should return packet

Design

sans I/O design

Fuzzing

Run the fuzzer with make fuzz. Crashes are written to __fuzz__/<target>/crashes/ and are committed so they replay on every cargo test.

Corpus dirs (__fuzz__/<target>/corpus/) are gitignored since they hold hundreds of small files that change on every run. Commit a tarball of the corpus instead. Run from the repo root so the tarball stores repo relative paths:

tar czf sim/src/fuzz/corpus.tar.gz sim/src/fuzz/__fuzz__/fuzz__raft/corpus

# restore
tar xzf sim/src/fuzz/corpus.tar.gz

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Resources

• https://toidiu.com/reads/In_Search_of_an_Understandable_Consensus_Algorithm_(Extended_Raft).pdf
• https://web.stanford.edu/~ouster/cgi-bin/papers/OngaroPhD.pdf
• https://notes.eatonphil.com/2023-05-25-raft.html
• https://github.com/jmsadair/raft
• https://github.com/tikv/raft-rs
• https://notes.eatonphil.com/2023-05-25-raft.html
• https://raft.github.io/
• http://dabeaz.com/raft.html