How to do distributed locking

ARANK

Published by Martin Kleppmann on 08 Feb 2016.As part of the research for my book, I came across an algorithm called Redlock on the Redis website. The algorithm claims to implement fault-tolerant distributed locks (or rather, leases [1]) on top of Redis, and the page asks for feedback from people who are into distributed systems. The algorithm instinctively set off some alarm bells in the back of my mind, so I spent a bit of time thinking about it and writing up these notes.Since there are already over 10 independent implementations of Redlock and we don’t know who is already relying on this algorithm, I thought it would be worth sharing my notes publicly. I won’t go into other aspects of Redis, some of which have already been critiqued elsewhere.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…