Kubernetes New Added 8 September 2026

Kubernetes: HorizontalPodAutoscaler unable to get metrics for resource cpu

The HPA has no metrics to scale on. Either metrics-server is not installed or not serving, or the pods have no CPU or memory requests: utilisation is a percentage of the request, so without one there is nothing to compute.

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

Quick fix

kubectl describe hpa myapp | tail -15
kubectl top pods            # fails the same way if metrics-server is down
kubectl get apiservices v1beta1.metrics.k8s.io

# Requests are mandatory for utilisation targets
resources:
  requests: { cpu: 100m, memory: 128Mi }

# Install or repair metrics-server
kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
kubectl -n kube-system logs deploy/metrics-server

How to diagnose Kubernetes errors

Kubernetes errors are best read as a state machine that got stuck. Pending means the scheduler could not place the pod (resources, taints, or an unbound volume). ImagePullBackOff means kubelet could not fetch the image (name, credentials, or registry). CrashLoopBackOff means the container starts and exits, so the answer is in the container's own logs. OOMKilled means the kernel killed it for exceeding its memory limit. Each state points at a different subsystem, and kubectl describe almost always contains the exact reason in its events.

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

Start with kubectl describe pod <name> and read the Events section at the bottom. It names the precise failure, including registry errors and scheduling constraints.
For CrashLoopBackOff, read the previous container's logs: kubectl logs <pod> --previous. The current container may not have produced output yet.
Check resource pressure with kubectl top pod and kubectl top node, and compare against the pod's requests and limits.
Test RBAC directly: kubectl auth can-i <verb> <resource> --as=system:serviceaccount:<ns>:<sa>. This answers permission questions definitively.
For networking, confirm the Service has endpoints (kubectl get endpoints) before suspecting DNS, Ingress or the CNI.

Tools worth reaching for

kubectl describe
kubectl logs --previous
kubectl auth can-i
kubectl top
kubectl events --sort-by=.lastTimestamp
k9s

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

kubernetes.io

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