How We Cut Rails on GKE Costs by 60%: The...

tl;dr: We reduced Google Kubernetes Engine(GKE) costs by 60%. The biggest wins came not from Kubernetes tuning, but from understanding why our Rails app needed so many Pods in the first place: Rails was running 1 Puma worker with 33 threads. Ruby's GVL made this effectively single-core. We switched to 4 workers with 8 threads. API authentication used bcrypt on every request. We replaced it with a lighter method. GKE node generation was outdated: upgrading from n1 to n2d gave 56% more CPU, 23% mo