Linux Foundation Certified Kubernetes Security Specialist (CKS) : CKS valid dump

Correct Answer:

Correct Answer:

See the Explanation belowExplanation:

Correct Answer:

See the Explanation below for complete solution
Explanation:
Below is the CKS exam-ready, step-by-step solution for QUESTION 15.
Follow exactly in this order. No extra changes.
QUESTION 15 - Istio mTLS (EXAM MODE)
1) Connect to the correct host
ssh cks000041
sudo -i
export KUBECONFIG=/etc/kubernetes/admin.conf
2) Ensure sidecar injection is enabled for the mtls namespace
2.1 Check current namespace labels
kubectl get ns mtls --show-labels
2.2 Enable automatic Istio sidecar injection
kubectl label namespace mtls istio-injection=enabled --overwrite
Verify:
kubectl get ns mtls --show-labels | grep istio-injection
Expected:
istio-injection=enabled
3) Ensure ALL Pods get the istio-proxy sidecar
Existing Pods will not get sidecars automatically.
You must restart workloads in the namespace.
3.1 Restart all Deployments in mtls
kubectl -n mtls rollout restart deployment
3.2 Verify Pods now have 2 containers (app + istio-proxy)
kubectl -n mtls get pods
Then check one Pod:
kubectl -n mtls get pod <pod-name> -o jsonpath='{.spec.containers[*].name}{"\n"}' Expected output includes:
istio-proxy
4) Configure mutual TLS (mTLS) in STRICT mode
4.1 Create a PeerAuthentication for the mtls namespace
cat <<EOF | kubectl apply -f -
apiVersion: security.istio.io/v1beta1
kind: PeerAuthentication
metadata:
name: mtls-strict
namespace: mtls
spec:
mtls:
mode: STRICT
EOF
5) Verify mTLS policy is applied
kubectl -n mtls get peerauthentication
kubectl -n mtls describe peerauthentication mtls-strict
Expected:
Mode: STRICT
6) Final verification (exam confidence check)
6.1 Confirm all Pods are Running
kubectl -n mtls get pods
6.2 Confirm sidecar injection everywhere
kubectl -n mtls get pods -o jsonpath='{range .items[*]}{.metadata.name}{" -> "}{.spec.containers[*].name}{"\n"}{end}' Each line must include istio-proxy.

Correct Answer:

See the Explanation belowExplanation:
[desk@cli] $ k create sa backend-qa -n qa
sa/backend-qa created
[desk@cli] $ k get role,rolebinding -n qa
No resources found in qa namespace.
[desk@cli] $ k create role backend -n qa --resource pods,namespaces,configmaps --verb list
# No access to secret
[desk@cli] $ k create rolebinding backend -n qa --role backend --serviceaccount qa:backend-qa
[desk@cli] $ vim /home/cert_masters/frontend-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: frontend
spec:
serviceAccountName: backend-qa # Add this
image: nginx
name: frontend
[desk@cli] $ k apply -f /home/cert_masters/frontend-pod.yaml
pod created
[desk@cli] $ k create sa backend-qa -n qa
serviceaccount/backend-qa created
[desk@cli] $ k get role,rolebinding -n qa
No resources found in qa namespace.
[desk@cli] $ k create role backend -n qa --resource pods,namespaces,configmaps --verb list role.rbac.authorization.k8s.io/backend created
[desk@cli] $ k create rolebinding backend -n qa --role backend --serviceaccount qa:backend-qa rolebinding.rbac.authorization.k8s.io/backend created
[desk@cli] $ vim /home/cert_masters/frontend-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: frontend
spec:
serviceAccountName: backend-qa # Add this
image: nginx
name: frontend
[desk@cli] $ k apply -f /home/cert_masters/frontend-pod.yaml
pod/frontend created
https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/

Correct Answer:

See the Explanation below for complete solution
Explanation:
Below is the CKS / CKA exam-style, exact step-by-step solution for Upgrading a kubeadm worker node.
Follow in order, type exact commands, no extra actions.
QUESTION - Upgrade node compute-0 (EXAM MODE)
1) Connect to the correct host (control plane)
ssh cks000034
sudo -i
export KUBECONFIG=/etc/kubernetes/admin.conf
2) Identify the control plane Kubernetes version
This is the target version for compute-0.
kubectl get nodes
Example output:
NAME STATUS ROLES VERSION
control-plane Ready control-plane v1.27.4
compute-0 Ready <none> v1.26.6
Note the control-plane version
Example: v1.27.4
3) Drain the compute node (do NOT modify workloads manually)
kubectl drain compute-0 --ignore-daemonsets --delete-emptydir-data
Wait until drain completes successfully.
4) SSH into the compute node
ssh compute-0
sudo -i
5) Check current kubeadm version on compute node
kubeadm version
6) Upgrade kubeadm to match control plane version
Replace 1.27.4 with the exact control-plane version you observed.
apt-get update
apt-get install -y kubeadm=1.27.4-00
Verify:
kubeadm version
7) Run kubeadm upgrade for the node
kubeadm upgrade node
✅ This updates node-specific configs (NO workloads touched).
8) Upgrade kubelet and kubectl to the same version
apt-get install -y kubelet=1.27.4-00 kubectl=1.27.4-00
9) Restart kubelet
systemctl daemon-reload
systemctl restart kubelet
systemctl status kubelet --no-pager
10) Exit the compute node (IMPORTANT)
exit
11) Uncordon the compute node (back on control plane)
kubectl uncordon compute-0
12) Final verification
kubectl get nodes
Expected:
NAME STATUS VERSION
compute-0 Ready v1.27.4