Free CKS Questions for Linux Foundation Certified Kubernetes Security Specialist (CKS) CKS Exam as PDF & Practice Test Engine
SIMULATION
Given an existing Pod named nginx-pod running in the namespace test-system, fetch the service-account-name used and put the content in /candidate/KSC00124.txt Create a new Role named dev-test-role in the namespace test-system, which can perform update operations, on resources of type namespaces.
Create a new RoleBinding named dev-test-role-binding, which binds the newly created Role to the Pod's ServiceAccount ( found in the Nginx pod running in namespace test-system).
Given an existing Pod named nginx-pod running in the namespace test-system, fetch the service-account-name used and put the content in /candidate/KSC00124.txt Create a new Role named dev-test-role in the namespace test-system, which can perform update operations, on resources of type namespaces.
Create a new RoleBinding named dev-test-role-binding, which binds the newly created Role to the Pod's ServiceAccount ( found in the Nginx pod running in namespace test-system).
Correct Answer:
See the Explanation belowExplanation:
SIMULATION
Context
This cluster uses containerd as CRI runtime.
Containerd's default runtime handler is runc. Containerd has been prepared to support an additional runtime handler, runsc (gVisor).
Task
Create a RuntimeClass named sandboxed using the prepared runtime handler named runsc.
Update all Pods in the namespace server to run on gVisor.
Context
This cluster uses containerd as CRI runtime.
Containerd's default runtime handler is runc. Containerd has been prepared to support an additional runtime handler, runsc (gVisor).
Task
Create a RuntimeClass named sandboxed using the prepared runtime handler named runsc.
Update all Pods in the namespace server to run on gVisor.
Correct Answer:
See the Explanation below
Explanation:
Explanation:
SIMULATION
Documentation Deployments, Pods, Falco
You must connect to the correct host . Failure to do so may result in a zero score.
[candidate@base] $ ssh cks000026
Context
A Pod is misbehaving and poses a security threat to the system.
Task
One of the Pods belonging to the application ollama is misbehaving. It is directly accessing the system's memory reading from the sensitive file /dev/mem.
First, identify the misbehaving Pod accessing /dev/mem.
The cluster uses the Docker Engine as its container runtime . If needed, use the docker command to troubleshoot running containers.
Next, identify the Deployment managing the misbehaving Pod and scale it to zero replicas.
Do not modify the Deployment except for scaling it down.
Do not modify any other Deployments .
Do not delete any Deployments.
Documentation Deployments, Pods, Falco
You must connect to the correct host . Failure to do so may result in a zero score.
[candidate@base] $ ssh cks000026
Context
A Pod is misbehaving and poses a security threat to the system.
Task
One of the Pods belonging to the application ollama is misbehaving. It is directly accessing the system's memory reading from the sensitive file /dev/mem.
First, identify the misbehaving Pod accessing /dev/mem.
The cluster uses the Docker Engine as its container runtime . If needed, use the docker command to troubleshoot running containers.
Next, identify the Deployment managing the misbehaving Pod and scale it to zero replicas.
Do not modify the Deployment except for scaling it down.
Do not modify any other Deployments .
Do not delete any Deployments.
Correct Answer:
See the Explanation below for complete solution
Explanation:
1) Connect to the correct host
ssh cks000026
sudo -i
2) Identify the misbehaving Pod accessing /dev/mem
This task hints Falco is available → use it first (fast + intended).
2.1 Check Falco logs for /dev/mem access
journalctl -u falco | grep dev/mem
If Falco runs as a pod instead of systemd:
kubectl -n falco logs -l app=falco | grep dev/mem
2.2 Identify the Pod name
From the Falco output, you will see something like:
Pod=ollama-xxxxx Namespace=default File=/dev/mem
Note the exact Pod name (example: ollama-7c9d6f7b6d-abcde)
3) (If Falco logs are unclear) Confirm using Docker runtime
Because the cluster uses Docker, verify which container is accessing /dev/mem.
3.1 List running containers
docker ps
3.2 Inspect suspicious container
(Find container related to ollama)
docker inspect <container_id> | grep ollama
You should confirm it maps to the same Pod you saw in Falco.
4) Identify the Deployment managing the misbehaving Pod
4.1 Get Pod details
kubectl get pod <MISBEHAVING_POD_NAME> -o wide
4.2 Find owning Deployment
kubectl get pod <MISBEHAVING_POD_NAME> -o jsonpath='{.metadata.ownerReference[0].name}' This will output something like:
ollama
That is the Deployment name
5) Scale ONLY that Deployment to zero replicas
Do not edit, delete, or touch anything else
kubectl scale deployment ollama --replicas=0
6) Verify the Pod is terminated
kubectl get pods | grep ollama
Expected: no running Pods
Also confirm replicas:
kubectl get deployment ollama
Replicas should show:
0/0
Explanation:
1) Connect to the correct host
ssh cks000026
sudo -i
2) Identify the misbehaving Pod accessing /dev/mem
This task hints Falco is available → use it first (fast + intended).
2.1 Check Falco logs for /dev/mem access
journalctl -u falco | grep dev/mem
If Falco runs as a pod instead of systemd:
kubectl -n falco logs -l app=falco | grep dev/mem
2.2 Identify the Pod name
From the Falco output, you will see something like:
Pod=ollama-xxxxx Namespace=default File=/dev/mem
Note the exact Pod name (example: ollama-7c9d6f7b6d-abcde)
3) (If Falco logs are unclear) Confirm using Docker runtime
Because the cluster uses Docker, verify which container is accessing /dev/mem.
3.1 List running containers
docker ps
3.2 Inspect suspicious container
(Find container related to ollama)
docker inspect <container_id> | grep ollama
You should confirm it maps to the same Pod you saw in Falco.
4) Identify the Deployment managing the misbehaving Pod
4.1 Get Pod details
kubectl get pod <MISBEHAVING_POD_NAME> -o wide
4.2 Find owning Deployment
kubectl get pod <MISBEHAVING_POD_NAME> -o jsonpath='{.metadata.ownerReference[0].name}' This will output something like:
ollama
That is the Deployment name
5) Scale ONLY that Deployment to zero replicas
Do not edit, delete, or touch anything else
kubectl scale deployment ollama --replicas=0
6) Verify the Pod is terminated
kubectl get pods | grep ollama
Expected: no running Pods
Also confirm replicas:
kubectl get deployment ollama
Replicas should show:
0/0
SIMULATION
A container image scanner is set up on the cluster.
Given an incomplete configuration in the directory
/etc/kubernetes/confcontrol and a functional container image scanner with HTTPS endpoint https://test-server.local.8081/image_policy
1. Enable the admission plugin.
2. Validate the control configuration and change it to implicit deny.
Finally, test the configuration by deploying the pod having the image tag as latest.
A container image scanner is set up on the cluster.
Given an incomplete configuration in the directory
/etc/kubernetes/confcontrol and a functional container image scanner with HTTPS endpoint https://test-server.local.8081/image_policy
1. Enable the admission plugin.
2. Validate the control configuration and change it to implicit deny.
Finally, test the configuration by deploying the pod having the image tag as latest.
Correct Answer:
SeetheExplanationbelowExplanation:
ssh-add ~/.ssh/tempprivate
eval "$(ssh-agent -s)"
cd contrib/terraform/aws
vi terraform.tfvars
terraform init
terraform apply -var-file=credentials.tfvars
ansible-playbook -i ./inventory/hosts ./cluster.yml -e ansible_ssh_user=core -e bootstrap_os=coreos -b --become-user=root --flush-cache -e ansible_user=core
ssh-add ~/.ssh/tempprivate
eval "$(ssh-agent -s)"
cd contrib/terraform/aws
vi terraform.tfvars
terraform init
terraform apply -var-file=credentials.tfvars
ansible-playbook -i ./inventory/hosts ./cluster.yml -e ansible_ssh_user=core -e bootstrap_os=coreos -b --become-user=root --flush-cache -e ansible_user=core
SIMULATION
Create a network policy named allow-np, that allows pod in the namespace staging to connect to port 80 of other pods in the same namespace.
Ensure that Network Policy:-
1. Does not allow access to pod not listening on port 80.
2. Does not allow access from Pods, not in namespace staging.
Create a network policy named allow-np, that allows pod in the namespace staging to connect to port 80 of other pods in the same namespace.
Ensure that Network Policy:-
1. Does not allow access to pod not listening on port 80.
2. Does not allow access from Pods, not in namespace staging.
Correct Answer:
See the Explanation belowExplanation:
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: network-policy
spec:
podSelector: {} #selects all the pods in the namespace deployed
policyTypes:
- Ingress
ingress:
- ports: #in input traffic allowed only through 80 port only
- protocol: TCP
port: 80
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: network-policy
spec:
podSelector: {} #selects all the pods in the namespace deployed
policyTypes:
- Ingress
ingress:
- ports: #in input traffic allowed only through 80 port only
- protocol: TCP
port: 80
SIMULATION
Create a new ServiceAccount named backend-sa in the existing namespace default, which has the capability to list the pods inside the namespace default.
Create a new Pod named backend-pod in the namespace default, mount the newly created sa backend-sa to the pod, and Verify that the pod is able to list pods.
Ensure that the Pod is running.
Create a new ServiceAccount named backend-sa in the existing namespace default, which has the capability to list the pods inside the namespace default.
Create a new Pod named backend-pod in the namespace default, mount the newly created sa backend-sa to the pod, and Verify that the pod is able to list pods.
Ensure that the Pod is running.
Correct Answer:
A service account provides an identity for processes that run in a Pod.
When you (a human) access the cluster (for example, using kubectl), you are authenticated by the apiserver as a particular User Account (currently this is usually admin, unless your cluster administrator has customized your cluster). Processes in containers inside pods can also contact the apiserver. When they do, they are authenticated as a particular Service Account (for example, default).
When you create a pod, if you do not specify a service account, it is automatically assigned the default service account in the same namespace. If you get the raw json or yaml for a pod you have created (for example, kubectl get pods/<podname> -o yaml), you can see the spec.serviceAccountName field has been automatically set.
You can access the API from inside a pod using automatically mounted service account credentials, as described in Accessing the Cluster. The API permissions of the service account depend on the authorization plugin and policy in use.
In version 1.6+, you can opt out of automounting API credentials for a service account by setting automountServiceAccountToken: false on the service account:
apiVersion: v1
kind: ServiceAccount
metadata:
name: build-robot
automountServiceAccountToken: false
...
In version 1.6+, you can also opt out of automounting API credentials for a particular pod:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
serviceAccountName: build-robot
automountServiceAccountToken: false
...
The pod spec takes precedence over the service account if both specify a automountServiceAccountToken value.
When you (a human) access the cluster (for example, using kubectl), you are authenticated by the apiserver as a particular User Account (currently this is usually admin, unless your cluster administrator has customized your cluster). Processes in containers inside pods can also contact the apiserver. When they do, they are authenticated as a particular Service Account (for example, default).
When you create a pod, if you do not specify a service account, it is automatically assigned the default service account in the same namespace. If you get the raw json or yaml for a pod you have created (for example, kubectl get pods/<podname> -o yaml), you can see the spec.serviceAccountName field has been automatically set.
You can access the API from inside a pod using automatically mounted service account credentials, as described in Accessing the Cluster. The API permissions of the service account depend on the authorization plugin and policy in use.
In version 1.6+, you can opt out of automounting API credentials for a service account by setting automountServiceAccountToken: false on the service account:
apiVersion: v1
kind: ServiceAccount
metadata:
name: build-robot
automountServiceAccountToken: false
...
In version 1.6+, you can also opt out of automounting API credentials for a particular pod:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
serviceAccountName: build-robot
automountServiceAccountToken: false
...
The pod spec takes precedence over the service account if both specify a automountServiceAccountToken value.
SIMULATION
Documentation
Installing the Sidecar, PeerAuthentication, Deployments
You must connect to the correct host . Failure to do so may result in a zero score.
[candidate@base] $ ssh cks000041
Context
A microservices-based application using unencrypted Layer 4 (L4) transport must be secured with Istio.
Task
Perform the following tasks to secure an existing application's Layer 4 (L4) transport communication using Istio.
Istio is installed to secure Layer 4 (L4) communications.
You may use your browser to access Istio's documentation.
First, ensure that all Pods in the mtls namespace have the istio-proxy sidecar injected.
Next, configure mutual authentication in strict mode for all workloads in the mtls namespace.
Documentation
Installing the Sidecar, PeerAuthentication, Deployments
You must connect to the correct host . Failure to do so may result in a zero score.
[candidate@base] $ ssh cks000041
Context
A microservices-based application using unencrypted Layer 4 (L4) transport must be secured with Istio.
Task
Perform the following tasks to secure an existing application's Layer 4 (L4) transport communication using Istio.
Istio is installed to secure Layer 4 (L4) communications.
You may use your browser to access Istio's documentation.
First, ensure that all Pods in the mtls namespace have the istio-proxy sidecar injected.
Next, configure mutual authentication in strict mode for all workloads in the mtls namespace.
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.
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.
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