Distributed State Controls — Redis Redlocks
BACKEND SERIES Day 28: Distributed State Controls — Redis Redlocks & Split-Brain Prevention 12 min read Series: Logic & Legacy Day 28 / 50 Level: Senior / Distributed Systems ⏳ Context: Yesterday, we implemented in-memory synchronization using asyncio.Lock and asyncio.Semaphore to protect single-process event loops. But when your backend scales out across 20 Kubernetes pods behind a load balancer, single-node locks offer zero protection. When Pod A and Pod B independently attempt to process the exact same payment or mutate the same database record simultaneously, your database becomes a battleground. To enforce multi-node mutual exclusion, we must step up to Distributed Locks using Redis and the Redlock algorithm. 1. The Naive Redis Lock Trap The simplest way developers attempt distributed locking is via SET key value NX PX 30000 . While this works in ideal network conditions, it introduces catastrophic failure modes when network pauses or GC freeze...
