Question

You are bringing up a brand-new Kubernetes cluster. The control plane is healthy and worker nodes show status Ready. However, every application Pod you create remains stuck in the ContainerCreating state, and 'kubectl describe pod' shows an event referencing 'failed to set up sandbox: networkPlugin cni failed to set up pod ... no CNI configuration found'. What is the most likely cause?

Accepted Answer

No Container Network Interface (CNI) plugin has been installed, so the kubelet cannot configure pod networking.

Answer

A default-deny NetworkPolicy is blocking all traffic to the new Pods.

Answer

The Service selector does not match the Pod labels, preventing traffic routing.

Answer

The PersistentVolumeClaim for the Pods cannot be bound to a PersistentVolume.