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Raft Consensus Under Failure

Walk one cluster through quorum commit, leader crash, election, log repair, and snapshot catch-up.

Amsterdamleaderterm 12 · last 416 · commit 416vote: self in term 12sending heartbeatsFrankfurtfollowerterm 12 · last 416 · commit 416vote: Amsterdamup to date voterMilanfollowerterm 12 · last 416 · commit 416vote: Amsterdamup to date voterBrusselsfollowerterm 12 · last 415 · commit 415vote: Amsterdamone entry behindAthensfollowerterm 12 · last 416 · commit 416vote: Amsterdamhealthy followerquorum5 voters, quorum size 3, leader is Amsterdamcommit ruleNo new command yet. Commit index stays at 416.safety stateOnly Amsterdam may extend the log in term 12.
Step 1 / 8Stable leader, stable quorum

Amsterdam is the leader for term 12. Everyone already agrees through commit index 416, and Brussels is one entry behind but still healthy enough to follow the leader.

Quorum picture
5 voters, quorum size 3, leader is Amsterdam
Commit boundary
No new command yet. Commit index stays at 416.
Why this matters
Only Amsterdam may extend the log in term 12.
Visible traffic

No single RPC dominates this frame. The important state change is the node role and log position shown above.

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