Raft Consensus Algorithm (2024)

Raft Visualization

Here's a Raft cluster running in your browser. You can interact with it to seeRaft in action. Five servers are shown on the left, and their logs are shown onthe right. We hope to create a screencast soon to explain what's going on. Thisvisualization (RaftScope)is still pretty rough around the edges; pull requests would be very welcome.

The Secret Lives of Datais a different visualization of Raft. It's more guided and less interactive, soit may be a gentler starting point.

Publications

This is "the Raft paper", which describes Raft in detail:In Search of an Understandable Consensus Algorithm (Extended Version)by Diego Ongaro andJohn Ousterhout.A slightly shorter version of this paper received a Best Paper Award at the2014 USENIX Annual Technical Conference.

Diego Ongaro'sPh.D. dissertationexpands on the content of the paper in much more detail, and it includes asimpler cluster membership change algorithm. The dissertation also includes aformal specification of Raft written in TLA+; a slightly updated version of thatspecification is here.

More Raft-related papers:

• Doug Woos, James R. Wilcox, Steve Anton, Zachary Tatlock, Michael D. Ernst, and Thomas Anderson.
  Planning for Change in a Formal Verification of the Raft Consensus Protocol.
  Certified Programs and Proofs (CPP), January 2016.

• James R. Wilcox, Doug Woos, Pavel Panchekha, Zachary Tatlock, Xi Wang, Michael D. Ernst, and Thomas Anderson.
  Verdi: A Framework for Implementing and Verifying Distributed Systems.
  Programming Language Design and Implementation (PLDI), June 2015.

• Hugues Evrard and Frédéric Lang.
  Automatic Distributed Code Generation from Formal Models of Asynchronous Concurrent Processes.
  Parallel, Distributed, and Network-Based Processing (PDP), March 2015.

• Heidi Howard, Malte Schwarzkopf, Anil Madhavapeddy, and Jon Crowcroft.
  Raft Refloated: Do We Have Consensus?.
  SIGOPS Operating Systems Review, January 2015.

• Heidi Howard.
  ARC: Analysis of Raft Consensus.
  University of Cambridge, Computer Laboratory, UCAM-CL-TR-857, July 2014.

Talks

These talks serve as good introductions to Raft:

• Talk on Raft at CS@Illinois Distinguished Lecture Series by John Ousterhout, August 2016:

  Video	YouTube
  Slides	PDF with RaftScope visualization

• Talk on Raft and its TLA+ spec as part of Dr. TLA+ Series by Jin Li, July 2016:

  Video	YouTube
  Slides	SlideShare

• Talk on Raft at Build Stuff 2015 by Diego Ongaro, November 2015:

  Video	InfoQ
  Slides	HTML PDF with RaftScope visualization

• Talks on Rust, Raft, and distributed systems at Rust Bay Area Meetup by Yvonne Coady, Diego Ongaro, Andrew Hobden, Dan Burkert, and Alex Newman, August 2015:

  Video	Air Mozilla
  Slides	Diego: PDF with RaftScope visualization

• Talk on Raft at CoreOS Fest 2015 by Diego Ongaro, May 2015:

  Video	YouTube
  Slides	PDF with RaftScope visualization

• Talk on Raft at Sourcegraph meetup by Diego Ongaro, April 2015:

  Video	YouTube
  Slides	PDF with RaftScope visualization

• Talk on Raft at LinkedIn by Diego Ongaro, September 2014:

  Video	YouTube
  Slides	PDF PPTX with RaftScope visualization

• Talk on Raft at USI 2014 and /dev/summer 2014 by Arnaud Bailly, July 2014:

  Video	YouTube (French)
  Slides	Speaker Deck (English)

• Talk on Raft at 2014 USENIX Annual Technical Conference by Diego Ongaro, June 2014:

  Video	USENIX
  Slides	RaftScope visualization

• Talk on Raft at CraftConf 2014 by Diego Ongaro, April 2014:

  Video	Ustream
  Slides	PDF PPTX

• Talk on Raft at Rubyconf 2013 by Patrick Van Stee, November 2013:

  Video	YouTube
  Slides	Speaker Deck

• Talk on Raft at RICON West 2013 by Diego Ongaro, October 2013:

  Video	YouTube
  Slides	PDF PPTX

• Talk on Raft at Strange Loop 2013 by Ben Johnson, September 2013:

  Video	InfoQ
  Slides	Speaker Deck

• Talk on Raft and Rafter at the Erlang NYC Meetup by Tom Santero and Andrew Stone, August 2013:

  Video	Vimeo
  Slides	Speaker Deck

• Talk on Raft (venue unknown) by Patrick Van Stee, July 2013:

  Slides

  Speaker Deck

• Lecture for the Raft User Study by John Ousterhout, March 2013:

  Video (screencast)	YouTube MP4
  Slides	PDF PPTX

Courses teaching Raft

This is a list of courses that include lectures or programming assignments on Raft.This might be useful for other instructors and for online learners looking for materials.If you know of additional courses, please submit apull requestor an issue to update it.

• University of Virginia, CS4740: Cloud Computing, Chang Lou. Includes lecture on Raft and programming assignment (Go). (Spring 2024 ...)
• University of California, San Deigo, CSE224: Graduate Networked Systems, George Porter. Includes lecture on Raft and programming assignment (Go) to develop a fault-tolerant Dropbox clone. (Winter 2023/2022, Fall 2020/2019/2018 ...)
• Technical University of Munich, IN2259: Distributed Systems, Pramod Bhatotia and Martin Kleppmann. Includes lecture on Raft. (Winter 2022/2023, ...)
• University of Illinois Urbana-Champaign, CS425: Distributed Systems, Indranil Gupta, Nikita Borisov, and Radhika Mittal. Includes Raft programming assignment in Go. (Spring 2021, ...)
• The Chinese University of Hong Kong, CSCI4160: Distributed and Parallel Computing (Private), Eric Lo. Includes lecture on Paxos and Raft as well as Raft programming assignment in Java/Go (Fall 2019, Spring 2021, ...)
• Indian Institute of Technology Delhi, COL 819: Distributed Systems, Smruti R. Sarangi. Includes lecture on Raft (video) (PPTX) (Winter 2020, ...)
• Carnegie Mellon University, CS 440: Distributed Systems, Yuvraj Agarwal, Dave Andersen. Includes Raft programming assignment in Go. (Fall 2019, ...)
• Northeastern University, CS 3700: Networks and Distributed Systems, Christo Wilson, Long Lu. Includes an assignment to build a replicated key-value store based on the Raft protocol. (Fall 2018, ...)
• Institute Technology Bandung, IF3230. Raft assignments with testcases for showcasing edge cases and scoring (2018)
• Rose-Hulman Institute of Technology, CS 403: Programming Language Paradigms, Buffalo Hewner. Includes Raft programming assignment in Erlang (assignments). (Winter 2017, ...)
• Princeton University, COS-418: Distributed Systems, Mike Freedman and Kyle Jamieson. Includes lecture on Raft (PPTX) and programming assignments to build a Raft-based key-value store. (Fall 2016, ...)
• University of Washington, CSE 452: Distributed Systems, Tom Anderson. Includes lecture on Raft, though they call it Paxos. (Winter 2016, ...)
• University of Colorado, Boulder, CSCI 5673: Distributed Systems, Shivakant Mishra. Includes assignment to download a Raft implementation and build a fault-tolerant data structure with it. (Fall 2015, ...)
• University of Utah, CS 6963: Distributed Systems, Ryan Stutsman (@rstutsman). Will include something about Raft (TBD). (Fall 2015, ...)
• San Jose State University, CMPE 275 Enterprise Application Development, John Gash. Includes project to make a distributed filesystem using Raft. (Spring 2015, ...)
• Brown, CS 138: Distributed Computer Systems, Tom Doeppner, Rodrigo Fonseca (@rodrigo_fonseca). Includes Raft programming assignment in Go. (Spring 2015, ...)
• MIT, 6.824: Distributed Systems, Robert Morris. Includes lecture on Raft (lecture notes). See Jon Gjengset's posts for instructors and students. (Spring 2015, ...)
• University of San Francisco, CS 636: Graduate Operating Systems, Greg Benson (@gregorydbenson). Includes lecture on Raft. (Spring 2015, ...)
• Harvard, CS 261: Research Topics in Operating Systems, Margo Seltzer. Includes lecture on Raft (lecture notes). (Fall 2014, ...)
• University of Houston, COSC 6360: Operating Systems, Jehan-François Pâris (@jehanfrancois). Includes lecture on Raft (PPT). (Fall 2014, ...)
• Stanford, CS 244b: Distributed Systems, Dawson Engler, David Mazières (@dmazieres). Included guest lecture on Raft by Diego Ongaro. Several students chose to work on Raft-based final projects. (Fall 2014)
• NUST-SEECS, CS 332: Distributed Computing, Tahir Azim (@TahirAzim). Includes lecture on Raft based on user study materials (tweet). (Fall 2014, ...)
• Duke, CPS 512: Distributed Systems, Bruce Maggs. Includes guest lecture on Raft (PPTX) by Landon Cox (@lpcox). (Spring 2014, Spring 2015, ...)
• IIT Bombay, CS 733: Cloud Computing, Sriram Srinivasan. Includes Raft programming assignment in Go (assignments). (Spring 2014, Spring 2015, ...)

Where can I ask questions?

The best place to ask questions about Raft and its implementations is theraft-dev Google group.Some of the implementations also have their own mailing lists; check their READMEs.

Where can I get Raft?

There are many implementations of Raft available in various stages ofdevelopment. This table lists the implementations we know about with sourcecode available. The most popular and/or recently updated implementations aretowards the top. This information will inevitably get out of date; please submit apull requestor an issue to update it.