Question

After bootstrapping a new single-control-plane cluster with kubeadm, you notice all nodes report NotReady and every Pod (including CoreDNS) remains stuck in ContainerCreating. Running 'kubectl describe pod' on a CoreDNS Pod shows the event: 'Failed to create pod sandbox: ... failed to find plugin "..." in path [/opt/cni/bin] ... network plugin is not ready: cni config uninitialized'. What is the correct action to bring the cluster to a healthy state?

Accepted Answer

Deploy a CNI plugin (e.g., apply the Calico or Flannel manifest) so the Pod network add-on initializes the node network.

Answer

Restart the kubelet on all nodes with 'systemctl restart kubelet' to force sandbox recreation.

Answer

Re-run 'kubeadm init' with the '--pod-network-cidr' flag to reconfigure the cluster networking.

Answer

Increase the CoreDNS Deployment replica count and add tolerations for the node.kubernetes.io/not-ready taint.