Concurrency

Over the last few years, I worked mostly on building microservices using Spring Boot, but I never really had a chance to work directly with distributed locking systems like Redis, ZooKeeper, or etcd. Still, I kept coming across these topics whenever I read about system design, schedulers, or how large systems avoid inconsistent updates. I always wanted to understand how distributed locks actually work and what could go wrong when multiple service instances try to modify the same shared resource.