Distributed Locking with Redis: Understanding the Redlock Algorithm
A single Redis instance makes a fine lock for a single-process app, but the moment you have multiple services racing to acquire the same lock — and that Redis instance can fail — a naive SETNX isn't safe anymore. Redlock, proposed by Redis's creator, is an algorithm for acquiring a distributed lock across multiple independent Redis nodes so that no single node's failure or slowness can silently break mutual exclusion.
This is genuinely advanced material — understanding it requires comfort with distributed systems failure modes, not just Redis commands.
Why a Single Redis Lock Isn't Enough
A basic lock looks simple:
