This alert is triggered when a Kubernetes node reports the NetworkUnavailable condition for more than 2 minutes. It indicates that the node’s networking is not properly configured or unavailable, preventing pods from communicating.

NetworkUnavailable can cause:

• Pods on the node being unable to communicate with each other or external services
• Application downtime or degraded performance
• Cluster components (kubelet, kube-proxy) failing to manage pods
• Scheduling and service disruptions

This alert is critical, as networking issues directly affect node and application availability.

Check node status:

kubectl get nodes
kubectl describe node <NODE_NAME>

Check network plugin status (e.g., CNI pods):

kubectl get pods -n kube-system
kubectl describe pod <CNI_POD_NAME> -n kube-system

Check kubelet logs for network errors:

journalctl -u kubelet -n 100

Check recent events for network-related issues:

kubectl get events --sort-by=.lastTimestamp

Verify node network interfaces and routes (if SSH access is available):

ip addr
ip route

• CNI plugin misconfiguration or failure
• Node network interface down or misconfigured
• Firewall or security group blocking traffic
• Cloud provider network issues
• Kubelet unable to configure networking due to errors

1. Restart CNI plugin pods:

kubectl delete pod <CNI_POD_NAME> -n kube-system

1. Restart kubelet service:

systemctl restart kubelet

1. Verify network configuration and routes on the node
2. Check firewall/security group rules
3. If cloud provider issue, contact provider support
4. If node cannot recover, cordon and drain it temporarily:

kubectl drain <NODE_NAME> --ignore-daemonsets --delete-emptydir-data
kubectl uncordon <NODE_NAME>

• If NetworkUnavailable persists beyond 10 minutes, escalate to the platform/network team
• Page on-call engineer if production workloads are impacted
• If multiple nodes are affected, treat as cluster-wide network incident

• KubernetesNodeNotReady
• KubeletDown
• PodCrashLoopBackOff
• NodeDown

• Grafana → Kubernetes / Node Network
• Grafana → CNI Plugin Metrics