Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
RAFT: Implementing Distributed Consensus with E...
Search
Tim McGilchrist
May 08, 2014
Programming
4
670
RAFT: Implementing Distributed Consensus with Erlang
Talk from Yow LambdaJam 2014 in Brisbane on RAFT Algorithm and implementing it in Erlang.
Tim McGilchrist
May 08, 2014
Tweet
Share
More Decks by Tim McGilchrist
See All by Tim McGilchrist
Dependently Typed State Machines
lambda_foo
0
160
Code reuse through polymorphic variants
lambda_foo
1
180
Either Error Success
lambda_foo
0
130
Idris States: Dependent types, not just for vectors?
lambda_foo
0
190
Other Decks in Programming
See All in Programming
NPOでのDevinの活用
codeforeveryone
0
840
ニーリーにおけるプロダクトエンジニア
nealle
0
850
dbt民主化とLLMによる開発ブースト ~ AI Readyな分析サイクルを目指して ~
yoshyum
3
1k
Webの外へ飛び出せ NativePHPが切り拓くPHPの未来
takuyakatsusa
2
560
A full stack side project webapp all in Kotlin (KotlinConf 2025)
dankim
0
120
ISUCON研修おかわり会 講義スライド
arfes0e2b3c
1
450
Azure AI Foundryではじめてのマルチエージェントワークフロー
seosoft
0
180
#kanrk08 / 公開版 PicoRubyとマイコンでの自作トレーニング計測装置を用いたワークアウトの理想と現実
bash0c7
1
770
地方に住むエンジニアの残酷な現実とキャリア論
ichimichi
5
1.6k
なぜ適用するか、移行して理解するClean Architecture 〜構造を超えて設計を継承する〜 / Why Apply, Migrate and Understand Clean Architecture - Inherit Design Beyond Structure
seike460
PRO
3
770
Result型で“失敗”を型にするPHPコードの書き方
kajitack
5
910
生成AI時代のコンポーネントライブラリの作り方
touyou
1
220
Featured
See All Featured
Build The Right Thing And Hit Your Dates
maggiecrowley
36
2.8k
Optimising Largest Contentful Paint
csswizardry
37
3.3k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.4k
Scaling GitHub
holman
460
140k
Practical Tips for Bootstrapping Information Extraction Pipelines
honnibal
PRO
20
1.3k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
367
26k
Embracing the Ebb and Flow
colly
86
4.7k
Refactoring Trust on Your Teams (GOTO; Chicago 2020)
rmw
34
3.1k
Performance Is Good for Brains [We Love Speed 2024]
tammyeverts
10
960
StorybookのUI Testing Handbookを読んだ
zakiyama
30
5.9k
Bootstrapping a Software Product
garrettdimon
PRO
307
110k
Six Lessons from altMBA
skipperchong
28
3.9k
Transcript
Tim McGilchrist @lambda_foo lambdafoo.com Raft Implementing Distributed Consensus with Erlang
Outline ❖ Goals! ❖ The consensus problem! ❖ Outline RAFT
algorithm! ❖ Implementing in Erlang
Goals What I want you to get out of this
talk?! • Understand core ideas in RAFT! • Erlang / OTP as a tool for building systems! • Build your own implementation
Consensus In a distributed system, agreement among multiple processes on
a single data value, despite failures. ! ! Once they reach a decision on a value, that decision is final.
Potential Use Case ❖ Configuration Management! ❖ Distributed Transactions! ❖
Distributed Lock Manager! ❖ DNS and Resource Discovery
RAFT ❖ Design for understandability! ❖ Strong leader! ❖ Practical
to implement Goals Raft is a consensus algorithm that is designed to be easy to understand.
Messages ❖ RAFT only needs 2 messages.! ❖ RequestVote includes
term! ❖ AppendEntries includes term and log entries! ❖ Term acts as a logical clock
States 3 states a node can be in. Follower Candidate!
Leader
Leader Leader • Only a single leader within a cluster!
• Receives commands from client! • Commits commands to the log
Follower Follower • Appends commands to log! • Votes for
candidates! • Otherwise passive
Candidate Candidate! • Initiates Election! • Coordinates Votes
Leader Election Follower Candidate! Leader starts up timeout new election
gets majority of votes step down step down timeout restart election
Log Replication add 1 F2 F1 Leader AppendEntries add 1,
index 0 add 1, index 0
Log Replication add 1 add 1 add 1 F2 F1
Leader Ok OK
Log Replication add 1 add 1 add 1 F2 F1
Leader Executes command
Log Replication add 1 add 4 add 1 add 1
F2 F1 Leader AppendEntries add 4, index 1 add 4, index 1 Executes command Executes command
RAFT Summary ❖ 2 types of messages, RequestVote and AppendEntries!
❖ 3 states, Leader, Follower and Candidate! ❖ Save Entries to persistent log
Erlang ❖ Functional language! ❖ Fundamentally a concurrent language! ❖
Actor model as basic abstraction! ❖ No shared state between actors! ❖ OTP behaviours like supervisors and gen_fsm! ❖ Location independent message sending
Implementation Overview ❖ github.com/tmcgilchrist/sloop ! ❖ github.com/andrewjstone/ rafter! ❖ Each
node has 2 supervised behaviours! ❖ gen_fsm implementing the consensus protocol! ❖ gen_server wraps the log store! ❖ passes erlang terms as messages
sloop_fsm ❖ state machine implements leader election and log replication!
❖ each state is a function with multiple clauses! !
Supervisors sloop_sup sloop_fsm sloop_store sloop_state sender
Implementations ! ❖ raftconsensus.github.io! ❖ github.com/tmcgilchrist/sloop ! ❖ github.com/andrewjstone/rafter !
❖ github.com/goraft/raft
Summary ❖ Defined Distributed Consensus! ❖ Looked at core ideas
of RAFT! ❖ Erlang suits distributed systems! ❖ Map Erlang to RAFT
Thanks!