Raft 04: A Key-Value Store on Top

The Scheduler build’s leader-election board, which says in one picture that something underneath has to answer “who is in charge, and is that still true”. Here the something is the log we just built, and the program on top is a store. Part of the Raft series, Build Your Own Raft.

Before you start. This series builds a small copy of Raft, the algorithm a group of machines uses to keep one shared list of commands. You have a leader election (Raft 01: Leader Election), a replicated log (Raft 02: Log Replication) and a log that survives restarts (Raft 03: Persistence). So far the commands were strings nobody read. This stage reads them: it makes a key-value store that a client can write to and read from, and answers the question the paper calls client interaction.