How to fix unable to compute new replica count for HPA: missing request metric in Kubernetes

What this error means

HPA performs a calculation: desiredReplicas = currentMetricValue / targetMetricValue * currentReplicas. When metric values are missing, NaN, or invalid, this calculation fails and HPA cannot determine the desired replica count. HPA will report status as "Unknown" and not change replica count.

Typical symptoms

• HPA status shows "Unknown" for desired replicas
• HPA events: "unable to compute new replica count"
• Metrics show as "unknown" in kubectl describe hpa
• Pod count does not change despite metric changes
• Missing metric values in HPA calculation
• Metric returns 0 or NaN for specific pods
• Inconsistent metric data from some replicas

Common causes

1. Pod missing from some metric queries (new pods)
2. Metric returns partial results (some pods missing)
3. Pod metrics include pods not in Service selector
4. Metric aggregation error (avg, sum, etc.)
5. Resource request missing from pod spec
6. Metric value is NaN or 0 for all pods
7. Custom metric not properly registered

How to fix "unable to compute new replica count for HPA: missing request metric"

Advanced notes

Related errors

• Failed to connect to server: connection refused (HTTP/2)

  How to fix "HTTP/2 connection refused" error in Kubernetes

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• missing request for cpu in container

  How to fix "missing request for cpu in container" in Kubernetes HPA

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• error: invalid configuration

  How to fix "error: invalid configuration" in Kubernetes

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Official resources & further reading

• 📚Kubernetes Official Documentation
• 📖
  Kubernetes Docs: Horizontal Pod Autoscaling(Official Docs)
• 📖
  Kubernetes Docs: Debugging Applications(Official Docs)
• 💬
  Stack Overflow: Kubernetes metrics server issues(Stack Overflow)