How to Do Distributed Locking
Before I go into the details of Redlock, let me say that I quite like Redis, and I have successfully used it in production in the past. I think it’s a good fit in situations where you want to share some transient, approximate, fast-changing data between servers, and where it’s not a big deal if you occasionally lose that data for whatever reason. For example, a good use case is maintaining request counters per IP address (for rate limiting purposes) and sets of distinct IP addresses per user ID (for abuse detection).