cks: swap kind CNI to Cilium, fix broken ingress-nginx setup

kindnet's NetworkPolicy enforcement isn't guaranteed, undermining the
Task 1 lab; Cilium (with kube-proxy replacement) enforces it
deterministically. Also fixes ingress-nginx, which was silently broken:
missing ingress-ready node label left the controller Pending forever,
and hostPorts 80/443 were never mapped in kind-config.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

kubernetes/cks/exam-by-claude/bootstrap.sh

@@ -1,32 +1,60 @@
 #!/usr/bin/env bash
 # CKS mock — cluster bootstrap. Run on your Ubuntu VM (needs docker, kind >= v0.32.0, kubectl v1.35, helm).
+# CNI is Cilium (kube-proxy replacement, no kindnet, no kube-proxy) — see kind-config.yaml's networking: block.
 set -euo pipefail
 
 HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 cd "$HERE"
 
+# ---- pinned versions ----
+CILIUM_VERSION="1.20.0"
+INGRESS_NGINX_REF="controller-v1.15.1"
+
 mkdir -p exam-files
 
 echo "[*] Creating kind cluster 'cks' (1 cp + 2 workers, k8s v1.35.5)..."
+# No --wait here: with disableDefaultCNI, nodes are legitimately NotReady (and CoreDNS Pending)
+# until Cilium is installed below — waiting now would just time out.
 kind create cluster --config kind-config.yaml
 kubectl config use-context kind-cks
 
+echo "[*] Installing Cilium v${CILIUM_VERSION} (CNI + kube-proxy replacement)..."
+CP_IP="$(docker inspect -f '{{.NetworkSettings.Networks.kind.IPAddress}}' cks-control-plane)"
+helm repo add cilium https://helm.cilium.io/ >/dev/null
+helm repo update cilium >/dev/null
+helm upgrade --install cilium cilium/cilium \
+  --version "$CILIUM_VERSION" --namespace kube-system \
+  --set ipam.mode=kubernetes \
+  --set kubeProxyReplacement=true \
+  --set k8sServiceHost="$CP_IP" --set k8sServicePort=6443 \
+  --set operator.replicas=1 \
+  --set image.pullPolicy=IfNotPresent \
+  --wait --timeout=5m
+
+echo "[*] Waiting for Cilium and nodes to be Ready..."
+kubectl -n kube-system rollout status ds/cilium --timeout=300s
+kubectl wait --for=condition=Ready nodes --all --timeout=300s
+command -v cilium >/dev/null 2>&1 && cilium status --wait || true
+
 echo "[*] Installing an ingress controller (needed for the TLS task)..."
-kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/kind/deploy.yaml
-kubectl -n ingress-nginx wait --for=condition=Ready pod \
-  -l app.kubernetes.io/component=controller --timeout=180s || true
+kubectl label node cks-control-plane ingress-ready=true --overwrite
+kubectl apply -f "https://raw.githubusercontent.com/kubernetes/ingress-nginx/${INGRESS_NGINX_REF}/deploy/static/provider/kind/deploy.yaml"
+kubectl -n ingress-nginx rollout status deploy/ingress-nginx-controller --timeout=300s
 
 cat <<'EOF'
 
 [*] Cluster up. Sanity check:
     kubectl get nodes -o wide
+    cilium status
+    kubectl -n kube-system get ds kube-proxy   # expected: not found — Cilium replaces it
 
 [*] Host-side tooling you want on the VM (install latest):
     - kube-bench   : https://github.com/aquasecurity/kube-bench/releases  (or run as a Job in-cluster)
     - trivy        : https://github.com/aquasecurity/trivy   (apt: aquasecurity repo)
     - kubesec      : https://github.com/controlplaneio/kubesec/releases
     - falco        : apt install falco   (v0.44.1) — used in the runtime task on the VM
-    - helm         : for Kyverno / Falco chart installs
+    - helm         : for Kyverno / Falco chart installs / Cilium (already used above)
+    - cilium-cli   : optional, https://github.com/cilium/cilium-cli/releases — `cilium status`/`cilium connectivity test`
     - cosign       : optional, image signing task
 
 [*] Now run ./seed.sh to plant the vulnerable/target objects for the kubectl-only tasks.