Why CPU-Based Autoscaling Fails for GPU Inference — and How KEDA Fixes It
By
Sneha Gullapalli
Summary
This article explains why CPU utilization is a poor autoscaling signal for GPU inference workloads, using a real-world incident where an HPA configured with targetCPUUtilizationPercentage failed to scale during a traffic spike, causing latency to spike. It argues that CPU is a decorrelated proxy on GPU pods — it can sit idle while the GPU is pinned and requests pile up. The article recommends scaling on signals actually on the critical path: queue depth (backlog) and GPU utilization, using KEDA (Kubernetes Event-Driven Autoscaling) for faster, more reliable scaling of AI workloads.
Source
Key quotes
· 3 pulledOn a GPU inference pod, CPU is a decorrelated proxy: it can sit at 30% while the accelerator is pinned and requests pile up behind it.
Scale on the signal actually on the critical path—backlog and GPU utilization—with KEDA.
Replica count stayed flat at two for eleven minutes while p99 latency went vertical and requests stacked up.
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