Focused, hands-on problems for sharpening your DevOps and server-side skills. Some teach specific concepts while others mirror real-world scenarios. Every challenge includes hints, feedback, and automated solution checks.
A worker node dropped to NotReady and part of the workload went with it. The container runtime is fine and the control plane is healthy; the trail leads from kubectl symptoms down into systemd and the kubelet configuration. Diagnose the node and bring it back.
Every kubectl command against a kubeadm cluster fails, and the workload is still serving. With no API to query, the usual tools tell you nothing. Work from the node itself to find what broke and bring the control plane back.
Learn how to reconfigure the Kubernetes cluster DNS domain by updating CoreDNS ConfigMap and kubelet configuration on all nodes, a critical skill for custom cluster networking and CKA exam preparation.
The production "Calendar Todo" web application has been deployed in the prod namespace but all pods are stuck in Pending. Investigate the cluster, identify why the application cannot run, fix the underlying node issue, and verify the app is serving traffic on NodePort 31777.
Create a static pod named mcp-grafana on node-01 and delete an existing pod from the cluster.
Did you know that pods can become invisible? Can you figure out how?
