Raft Essentials, and What It Does Not Guarantee

1. The Problem Consensus Solves

Consensus is a set of machines agreeing on a value when some of them can fail and the network between them can delay or drop messages. Raft solves a specific version of it: agreeing on an ordered log of commands.

That framing matters, because it explains what you get. If every node applies the same commands in the same order to the same starting state, every node reaches the same state. A replicated state machine is not a separate feature. It falls out of agreeing on the log.

Raft organizes this around one idea that makes the rest readable.

There is at