CKA Exam study 2026 Scenario 1 - The etcd Endpoint Trap

The etcd Endpoint Trap A cluster migration just took your whole control plane offline. In the next few minutes you'll find out why, and fix it the way the CKA exam expects. This is a CKA Troubleshooting walkthrough. Every command below is real output from a live cluster, and you can reproduce the whole thing yourself (scripts at the end). The scenario A single-node kubeadm cluster was migrated to a new machine. The control plane won't come up. Your task: identify the broken component, find the root cause, fix the config, restart, and verify. Single-node kubeadm cluster, freshly migrated Control plane will not start Find the broken component Root-cause it, fix it, verify How the control plane actually starts The kubelet runs the control plane as static pods from /etc/kubernetes/manifests . The kube-apiserver cannot start unless it can reach etcd. Give it the wrong etcd address and the apiserver crashes, so the whole cluster looks dead. The kube-apiserver runs as a static pod : the kubelet reads its manifest from /etc/kubernetes/manifests/ and keeps it running. The apiserver cannot start unless it can reach etcd, so a wrong --etcd-servers endpoint takes the whole API down, and with it, everything you'd normally use to debug. Step 1 — Reproduce the symptom First, reproduce the symptom. kubectl get nodes is refused. A refused connection on the API port means the API server is down: a control-plane problem, not a workload problem. $ kubectl get nodes The connection to the server cka-scenario1-control-plane:6443 was refused - did you specify the right host or port? A refused connection on the API port is a control-plane problem, not a workload problem. Step 2 — Investigate from the node kubectl can't help us now, so drop to the node. The kubelet itself is active. But follow its log and you'll see it stuck in a loop, restarting the apiserver over and over. The kubelet is fine; the static pod it manages is the problem. $ systemctl is-active kubelet active $ journalctl -u ku