How to fix network plugin is not ready: cni config uninitialized in Kubernetes

What this error means

The "network plugin is not ready: cni config uninitialized" error indicates that Kubernetes cannot initialize pod networking because no CNI (Container Network Interface) plugin is installed or configured. This is a critical error that prevents nodes from becoming Ready and blocks all pod scheduling. After running kubeadm init, Kubernetes creates the control plane but doesn't include a network plugin—you must install one separately. The kubelet waits for CNI configuration files in /etc/cni/net.d/ and plugin binaries in /opt/cni/bin/. Without these, nodes remain NotReady. This error commonly occurs on fresh cluster installations before applying a network add-on, or when CNI plugin pods crash or get deleted.

Typical symptoms

• kubectl get nodes shows nodes in NotReady status
• kubectl describe node shows NetworkUnavailable=True condition
• CoreDNS pods stuck in Pending state
• Kubelet logs show repeated "cni config uninitialized" errors
• No pods can be scheduled on affected nodes
• Missing cni0 network interface on nodes

Common causes

1. No CNI plugin installed after kubeadm init
2. CNI plugin binaries missing from /opt/cni/bin/
3. No CNI configuration in /etc/cni/net.d/
4. CNI version mismatch between config and plugin
5. Missing --pod-network-cidr flag during cluster initialization

How to fix "network plugin is not ready: cni config uninitialized"

# Enable immediately
sudo sysctl -w net.ipv4.ip_forward=1
sudo sysctl -w net.bridge.bridge-nf-call-iptables=1
sudo modprobe br_netfilter

# Persist across reboots
cat <<EOF | sudo tee /etc/sysctl.d/99-kubernetes-cni.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF
sudo sysctl -p /etc/sysctl.d/99-kubernetes-cni.conf

apt-get update && apt-get install -y kubernetes-cni
sudo systemctl restart kubelet

# For Flannel (use 10.244.0.0/16)
sudo kubeadm init --pod-network-cidr=10.244.0.0/16

# For Calico (use 192.168.0.0/16)
sudo kubeadm init --pod-network-cidr=192.168.0.0/16

kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml

# Wait for flannel pods
kubectl wait --for=condition=ready pod -l app=flannel -n kube-flannel --timeout=300s

# Verify cni0 interface created
ip link show | grep cni0

# Check node status
kubectl get nodes

# Install Calico operator
kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.1/manifests/tigera-operator.yaml

# Wait for CRD
kubectl wait --for=condition=Established crd/installations.operator.tigera.io --timeout=300s

# Install Calico
kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.1/manifests/custom-resources.yaml

# Verify pods running
kubectl get pods -n calico-system

# Check node status
kubectl get nodes

# List CNI configs
ls -la /etc/cni/net.d/

# Check config content
cat /etc/cni/net.d/*.conflist

# List CNI binaries
ls -la /opt/cni/bin/

# Check containerd can see CNI
grep -A5 "plugins" /etc/containerd/config.toml

sudo systemctl restart containerd
sudo systemctl restart kubelet

# View kubelet logs
journalctl -u kubelet -f | grep -i cni

# View containerd logs
journalctl -u containerd -f | grep -i cni

# Check node conditions
kubectl describe node <node-name>
# Look for: NetworkUnavailable condition

# View CNI plugin pod logs
kubectl logs -n kube-system -l k8s-app=flannel --tail=100

Advanced notes

Frequently asked questions

What does "network plugin is not ready: cni config uninitialized" mean?

The "network plugin is not ready: cni config uninitialized" error indicates that Kubernetes cannot initialize pod networking because no CNI (Container Network Interface) plugin is installed or configured. This is a critical error that prevents nodes from becoming Ready and blocks all pod scheduling. After running kubeadm init, Kubernetes creates the control plane but doesn't include a network plugin—you must install one separately.

How do I fix "network plugin is not ready: cni config uninitialized"?

This error occurs when the CNI (Container Network Interface) plugin is not installed or configured. Fix it by installing a CNI plugin like Calico, Flannel, or Cilium and ensuring system prerequisites like IP forwarding are enabled.

What causes "network plugin is not ready: cni config uninitialized"?

No CNI plugin installed after kubeadm init CNI plugin binaries missing from /opt/cni/bin/ No CNI configuration in /etc/cni/net.d/

Is the "network plugin is not ready: cni config uninitialized" error serious?

Yes. This is a critical-severity error that usually blocks work until it is fixed, but the steps above resolve it.

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Official resources & further reading

• 📚Kubernetes Official Documentation
• 📖
  Kubernetes Docs: Troubleshooting CNI Plugin Errors(Official Docs)
• 🐙
  GitHub: network plugin is not ready(GitHub)
• 💬
  Stack Overflow: CNI plugin not ready(Stack Overflow)