Raft — the quiet machinery of agreement

Five machines, no shared clock, no trusted center. They fail, they split, they rejoin — and still they must agree on a single, ordered story of what happened. Watch them do it. Then see the one geometric fact that makes it safe.

Speed

Click any node to crash or revive it. A crashed node freezes — it stops timing out, voting, and replicating.

network partitioned
Follower Candidate Leader Uncommitted entry Committed (majority holds it) bar = election countdown · tⁿ = term an entry was created in

Event log

Every election, vote, commit, and step-down, in the order it happened.

Why nothing committed is ever lost

The whole safety of Raft rests on one fact about the number five.

Majority A — 3 of 5
Majority B — 3 of 5

A faithful but compact model of the Raft consensus algorithm (Ongaro & Ousterhout, 2014). Some details are simplified for legibility — see notes in the source. Built to be read, not deployed.