Challenges

Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.

Challenge

CKA Practice: Renew Expiring Control Plane Certificates

kubectl is dead: the kube-apiserver certificate expired and the control plane is down, while the workload quietly keeps serving. Diagnose the expiry offline, renew the certificates, bring the control plane back, and prove the cluster recovered.

Challenge

Issue Per-Pod mTLS Certificates with PodCertificateRequest

Kubernetes 1.37 can hand every pod its own short-lived X.509 identity, no service mesh and no sidecar involved. The API is served out of the box, but it issues nothing without a signer, and a request nobody answers leaves the pod waiting forever. Get a stalled workload its certificates, give its client an identity of its own, and make the server actually enforce mutual TLS.