Distributed Consensus with Raft - CodeConf 2016

Presented by John Feminella

Getting people to agree to things is sometimes hard. But implementing consensus with computers is harder. And distributed consensus with computers is ​really​ hard. How do we do it?

In this talk, we’ll explore one idea of how distributed consensus can work, which the authors call ​Raft​, with several popular open-source implementations. Along the way, we’ll learn about why consensus is challenging, how Raft works in practice, and see a real live example of a system that depends on Raft.

About CodeConf
CodeConf improves the software community by providing a forum for thought-provoking talks and forging social connections. The fourth installment of the CodeConf series took place in Hollywood in 2016. This year's event focused on systems engineering projects, practices, and programs in the open source community.

For more information on this year's CodeConf, go to:

[jodo]

Thanks Dr Feminella, you have an excellent teaching style and I expect that you are a credit to your students. Bravo.

[horeaporutiu]

Wow this is incredible. Best raft video on YouTube I’ve seen so far

[kit-tara]

How amazing you are by preparing this lesson. You got me examples with explanations within the reasons. I love that, that you so much

[franciscolopezsancho]

Many thanks, John. This is great work, thanks for throwing quite a bit of light over the algorithm!

[bminerrolltide]

John - great job explaining this! I could probably implement Raft just based on the video. When you spoke about "Commitment issues", you mention the rules for determining if a log entry is committed or not. These rules hold because of the election rules. This was not entirely clear to me until a few minutes after I watched your video. :)

[Aditya-nelk]

so much better than the hashconf one lol

[jakubbujny]

Very good video to learn what Raft actually is!

[minhnhat]

@GitHub in 16:46, how can S1 win an election and be a leader of term 3 without having the majority nodes in term 3 ( S2, S3 and S4 still in term 2)? I'm trying to reconstruct the example cluster in video but I cannot think up how John can do it.

[jayshah]

Great talk! Is there a link to that simulator tool?

[jmmtechnology]

Great explanation, however I'm still unclear on the scenario where a client reads from the cluster and the data isn't fully replicated to all the followers. I'm guessing the data is read up to the last committed log in the leader?

[kirank]

Thanks, John, that we very informative and helpful. It seems that RAFT is a better system for implementing Cryptocurrency than Blockchain, is there an implementation of it out there? Or not? Why is there no focus on RAFT consensus instead of Blockchain based consensus?