How to fix Kubelet API authentication failed in Kubernetes

KubernetesADVANCEDHIGH

This error occurs when the API server cannot authenticate to a kubelet on a worker node, preventing node communication and pod operations.

What this error means

The "Kubelet API authentication failed" error indicates that the API server cannot authenticate itself when communicating with kubelets on worker nodes.

Typical symptoms

Node shows NotReady
Kubelet logs show auth errors
Pods fail to start on node

Common causes

Kubelet certificate expired
API server cert misconfigured
Node authorization policy changed

How to fix "Kubelet API authentication failed"

1Check node status

kubectl get nodes

2Check kubelet logs

kubectl logs -n kube-system -l component=kubelet

3Verify certificates

openssl x509 -in /var/lib/kubelet/pki/kubelet.crt -noout -dates

4Check API server logs

kubectl logs -n kube-system pod/kube-apiserver-<node>

Advanced notes

Kubelet authentication uses x509 certificates. Ensure certs are valid and API server has correct node authorization.

Related errors

Official resources & further reading

📚Kubernetes Official Documentation
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Kubernetes Docs: Kubelet Authentication and Authorization(Official Docs)
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Kubernetes Docs: Managing Kubelet(Official Docs)
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Stack Overflow: Kubelet authentication issues(Stack Overflow)