Node and Capacity Spillover: What Happens When Kubernetes Runs Out of Room

A pod stuck in Pending is one of the most misleading states in Kubernetes. Nothing looks wrong. There's no error banner, no red text screaming at you. The scheduler just quietly gave up finding a home for it and is waiting for the world to change.

I've stared at that status more times than I'd like to admit, usually at the worst possible hour, usually while someone in a chat window is asking why traffic isn't going through. Eleven minutes is about how long it took once, on a cluster that had close to 40% CPU sitting free the entire time. That gap between "there's capacity somewhere" and "this pod actually got scheduled" is what this article is really about.