EC
NetworkNotReady
KubernetesERRORCommonNetworkHIGH confidence

CNI plugin not ready — pods cannot get network interfaces

Production Risk

All pods on the affected node cannot obtain network interfaces; no new pods can start on that node.

What this means

NetworkNotReady means the Container Network Interface (CNI) plugin on a node has not reported ready, or is not installed. Pods scheduled to this node will be stuck in ContainerCreating because kubelet cannot set up network namespaces or assign IP addresses. This typically occurs during node bootstrap, after a CNI plugin crash, or when the CNI binary is missing.

Why it happens
  1. 1CNI plugin DaemonSet pod is not running on the node (crash, eviction, pending)
  2. 2CNI configuration files are missing from /etc/cni/net.d/ on the node
  3. 3CNI binary is not present in /opt/cni/bin/ on the node
  4. 4Node just joined the cluster and CNI DaemonSet has not yet been scheduled
How to reproduce

Pods on a specific node are stuck in ContainerCreating; node may show NetworkUnavailable=True.

trigger — this will error
trigger — this will error
kubectl describe node mynode | grep -A 5 "Conditions:"
# NetworkUnavailable   True   ...   CniPluginUninitialized

kubectl get pods -n kube-system -o wide | grep cni | grep mynode

expected output

NetworkUnavailable   True    ...   CniPluginUninitialized

Fix 1

Check CNI DaemonSet pod on the affected node

WHEN Pods on one node are stuck in ContainerCreating

Check CNI DaemonSet pod on the affected node
kubectl get pods -n kube-system -o wide | grep -E "calico|flannel|weave|cilium" | grep mynode
kubectl describe pod <cni-pod-name> -n kube-system

Why this works

Identifies whether the CNI DaemonSet pod is running on the affected node.

Fix 2

Reinstall or restart the CNI plugin

WHEN CNI pod is crashing or missing

Reinstall or restart the CNI plugin
# Delete the crashing CNI pod to trigger a restart
kubectl delete pod <cni-pod-name> -n kube-system

# For Calico
kubectl rollout restart daemonset calico-node -n kube-system

Why this works

Forces the DaemonSet to recreate the CNI pod on the node, re-initialising the network plugin.

Sources
Official documentation ↗

Kubernetes Documentation

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