Diagnose and resolve cluster, node, and application issues in Kubernetes environments (30% of exam).
This domain covers troubleshooting clusters and nodes, troubleshooting cluster components, monitoring cluster and application resource usage, managing and evaluating container output streams, and troubleshooting services and networking. This is the largest exam domain, reflecting the critical importance of troubleshooting skills for Kubernetes administrators.
5 minutes
5 Questions
Troubleshooting is a significant domain in the Certified Kubernetes Administrator (CKA) exam, accounting for approximately 30% of the curriculum. It requires a hierarchical approach to diagnosis, moving from the Application layer to the Worker Nodes, and finally to the Control Plane.
At the **Application/Pod level**, the primary tools are `kubectl get`, `describe`, and `logs`. If a Pod is in a `Pending` state, `kubectl describe` reveals scheduling issues (e.g., insufficient CPU/Memory or Taints/Tolerations). If the status is `CrashLoopBackOff`, `kubectl logs` is essential to identify runtime errors. Networking issues at this level often involve debugging Services and CoreDNS to ensuring proper Endpoint discovery.
At the **Worker Node level**, issues usually manifest as nodes reporting a `NotReady` status. This requires SSH access to the node to inspect the Kubelet. Essential commands include `systemctl status kubelet` to verify the service is running and `journalctl -u kubelet` to read system logs. Common causes include misconfigured CNI plugins, certificate mismatches in `kubeconfig`, or container runtime (CRI) failures.
**Control Plane** troubleshooting focuses on the API Server, Scheduler, Controller Manager, and etcd. Since these often run as Static Pods, you must examine the manifest files in `/etc/kubernetes/manifests` for configuration errors, such as typos in command arguments or volume mounts. If the API server is down, `kubectl` will not work, requiring you to analyze container logs directly on the master node (e.g., using `crictl` or `docker`). Furthermore, you must be proficient in diagnosing etcd cluster health and performing backup restores.
Success in CKA troubleshooting relies on quickly isolating the failure domain and effectively using imperative commands to validate fixes.Troubleshooting is a significant domain in the Certified Kubernetes Administrator (CKA) exam, accounting for approximately 30% of the curriculum. It requires a hierarchical approach to diagnosis, moving from the Application layer to the Worker Nodes, and finally to the Control Plane.
At the **Appl…