AKS Scaling Crisis: The Hidden 100-Backend Pool Trap
Kubernetes deployments look perfect—until traffic mysteriously stops. That’s exactly what happened when an Azure Kubernetes Service cluster using Application Gateway Ingress Controller hit Azure’s hard 100-backend pool limit. The issue is deceptively silent: Kubernetes resources apply successfully, but the Application Gateway rejects the 101st backend pool, breaking ingress for new applications.
This real-world case study reveals how a common deployment pattern—one Service and Ingress per application—triggers this ceiling, complete with reproduction steps and the exact AGIC error message. More importantly, it maps three mitigation paths, with Gateway API-based routing emerging as the strategic long-term solution, despite being in preview.
If you’re running AGIC at scale, this is the warning you can’t afford to miss.