cks-final/submissions/CKS-018-completed.md

CKS-018 — Disable anonymous API access

Domain: 2.3 Restrict Kubernetes API access
Time: 5 minutes · Score: Section B only

Complete exercise manifest

/etc/kubernetes/manifests/kube-apiserver.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: kube-apiserver
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-apiserver
    image: registry.k8s.io/kube-apiserver:v1.35.0
    command:
    - kube-apiserver
    - --advertise-address=10.0.0.10
    - --anonymous-auth=true
    - --authorization-mode=Node,RBAC
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
    - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
    - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
    - --etcd-servers=https://127.0.0.1:2379
    - --secure-port=6443
    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
    volumeMounts:
    - name: pki
      mountPath: /etc/kubernetes/pki
      readOnly: true
  volumes:
  - name: pki
    hostPath:
      path: /etc/kubernetes/pki
      type: DirectoryOrCreate

Task

Back up the manifest outside its directory, disable anonymous authentication, wait for API recovery, then verify authenticated readiness and that an unauthenticated request to https://127.0.0.1:6443/api returns HTTP 401.

Section B — scored answer

cp /etc/kubernetes/manifests/kube-apiserver.yaml ~/kube-apiserver.yaml-$(date +%Y-%m-%d)
nano /etc/kubernetes/manifests/kube-apiserver.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kube-apiserver
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-apiserver
    image: registry.k8s.io/kube-apiserver:v1.35.0
    command:
    - kube-apiserver
    - --advertise-address=10.0.0.10
    - --anonymous-auth=false
    - --authorization-mode=Node,RBAC
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
    - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
    - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
    - --etcd-servers=https://127.0.0.1:2379
    - --secure-port=6443
    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
    volumeMounts:
    - name: pki
      mountPath: /etc/kubernetes/pki
      readOnly: true
  volumes:
  - name: pki
    hostPath:
      path: /etc/kubernetes/pki
      type: DirectoryOrCreate

kubectl get --raw='/readyz'
curl -k -s -o /dev/null -w "%{http_code}\n" https://127.0.0.1:6443/api 

Say Grade CKS-018 when saved.