[2025] Pass Linux Foundation CKS Exam Updated 49 Questions
Get 2025 Updated Free Linux Foundation CKS Exam Questions and Answer
The CKS exam was created to ensure candidates have the necessary knowledge of Kubernetes security and practical, hands-on experience necessary to secure Kubernetes environments effectively. Certified Kubernetes Security Specialist (CKS) certification is designed for individuals who administer Kubernetes clusters and deployments, which includes but not limited to System Administrators, DevOps Engineers, Security Specialists, and Operations Engineers. As Kubernetes continues to grow in popularity, this certification allows professionals to differentiate themselves, demonstrate their knowledge and gain a competitive edge in the industry.
Linux Foundation CKS exam is an essential certification for professionals who work with Kubernetes environments. It validates the skills and knowledge necessary to secure containerized applications deployed on Kubernetes clusters. The CKS certification is highly valued in the industry and can help professionals advance their careers in the field of container security.
The CKS certification exam is intended for professionals who have a solid understanding of Kubernetes architecture and security concepts. It is also ideal for those who are responsible for securing Kubernetes clusters in their organizations. CKS exam covers various topics, including Kubernetes installation and configuration, network security, access management, and Kubernetes cluster hardening. CKS exam is designed to test the candidate’s ability to identify and mitigate security threats in a Kubernetes environment.
NEW QUESTION # 22
SIMULATION
Create a RuntimeClass named gvisor-rc using the prepared runtime handler named runsc.
Create a Pods of image Nginx in the Namespace server to run on the gVisor runtime class
Answer:
Explanation:
Install the Runtime Class for gVisor
{ # Step 1: Install a RuntimeClass
cat <<EOF | kubectl apply -f -
apiVersion: node.k8s.io/v1beta1
kind: RuntimeClass
metadata:
name: gvisor
handler: runsc
EOF
}
Create a Pod with the gVisor Runtime Class
{ # Step 2: Create a pod
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
name: nginx-gvisor
spec:
runtimeClassName: gvisor
containers:
- name: nginx
image: nginx
EOF
}
Verify that the Pod is running
{ # Step 3: Get the pod
kubectl get pod nginx-gvisor -o wide
}
NEW QUESTION # 23
Create a RuntimeClass named untrusted using the prepared runtime handler named runsc.
Create a Pods of image alpine:3.13.2 in the Namespace default to run on the gVisor runtime class.
Answer:
Explanation:
NEW QUESTION # 24
Context
AppArmor is enabled on the cluster's worker node. An AppArmor profile is prepared, but not enforced yet.
Task
On the cluster's worker node, enforce the prepared AppArmor profile located at /etc/apparmor.d/nginx_apparmor.
Edit the prepared manifest file located at /home/candidate/KSSH00401/nginx-pod.yaml to apply the AppArmor profile.
Finally, apply the manifest file and create the Pod specified in it.
Answer:
Explanation:
NEW QUESTION # 25
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. Send us the Feedback on it.
Answer: A
NEW QUESTION # 26
Context:
Cluster: gvisor
Master node: master1
Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context gvisor
Context: This cluster has been prepared to support runtime handler, runsc as well as traditional one.
Task:
Create a RuntimeClass named not-trusted using the prepared runtime handler names runsc.
Update all Pods in the namespace server to run on newruntime.
Answer:
Explanation:
Find all the pods/deployment and edit runtimeClassName parameter to not-trusted under spec
[desk@cli] $ k edit deploy nginx
spec:
runtimeClassName: not-trusted. # Add this
Explanation
[desk@cli] $vim runtime.yaml
apiVersion: node.k8s.io/v1
kind: RuntimeClass
metadata:
name: not-trusted
handler: runsc
[desk@cli] $ k apply -f runtime.yaml
[desk@cli] $ k get pods
NAME READY STATUS RESTARTS AGE
nginx-6798fc88e8-chp6r 1/1 Running 0 11m
nginx-6798fc88e8-fs53n 1/1 Running 0 11m
nginx-6798fc88e8-ndved 1/1 Running 0 11m
[desk@cli] $ k get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 11 3 5m
[desk@cli] $ k edit deploy nginx
NEW QUESTION # 27
Cluster: qa-cluster
Master node: master Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context qa-cluster
Task:
Create a NetworkPolicy named restricted-policy to restrict access to Pod product running in namespace dev.
Only allow the following Pods to connect to Pod products-service:
1. Pods in the namespace qa
2. Pods with label environment: stage, in any namespace
Answer:
Explanation:
$ k get ns qa --show-labels
NAME STATUS AGE LABELS
qa Active 47m env=stage
$ k get pods -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
product 1/1 Running 0 3s env=dev-team
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: restricted-policy
namespace: dev
spec:
podSelector:
matchLabels:
env: dev-team
policyTypes:
- Ingress
ingress:
- from:
- namespaceSelector:
matchLabels:
env: stage
- podSelector:
matchLabels:
env: stage
[desk@cli] $ k get ns qa --show-labels
NAME STATUS AGE LABELS
qa Active 47m env=stage
[desk@cli] $ k get pods -n dev --show-labels
NAME READY STATUS RESTARTS AGE LABELS
product 1/1 Running 0 3s env=dev-team
[desk@cli] $ vim netpol2.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: restricted-policy
namespace: dev
spec:
podSelector:
matchLabels:
env: dev-team
policyTypes:
- Ingress
ingress:
- from:
- namespaceSelector:
matchLabels:
env: stage
- podSelector:
matchLabels:
env: stage
[desk@cli] $ k apply -f netpol2.yaml Reference: https://kubernetes.io/docs/concepts/services-networking/network-policies/
[desk@cli] $ k apply -f netpol2.yaml Reference: https://kubernetes.io/docs/concepts/services-networking/network-policies/
NEW QUESTION # 28
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.
Answer:
Explanation:
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
NEW QUESTION # 29
Context
Your organization's security policy includes:
ServiceAccounts must not automount API credentials
ServiceAccount names must end in "-sa"
The Pod specified in the manifest file /home/candidate/KSCH00301 /pod-m nifest.yaml fails to schedule because of an incorrectly specified ServiceAccount.
Complete the following tasks:
Task
1. Create a new ServiceAccount named frontend-sa in the existing namespace q a. Ensure the ServiceAccount does not automount API credentials.
2. Using the manifest file at /home/candidate/KSCH00301 /pod-manifest.yaml, create the Pod.
3. Finally, clean up any unused ServiceAccounts in namespace qa.
Answer:
Explanation:
NEW QUESTION # 30
SIMULATION
Secrets stored in the etcd is not secure at rest, you can use the etcdctl command utility to find the secret value for e.g:- ETCDCTL_API=3 etcdctl get /registry/secrets/default/cks-secret --cacert="ca.crt" --cert="server.crt" --key="server.key" Output
Using the Encryption Configuration, Create the manifest, which secures the resource secrets using the provider AES-CBC and identity, to encrypt the secret-data at rest and ensure all secrets are encrypted with the new configuration.
- A. Send us the Feedback on it.
Answer: A
NEW QUESTION # 31
SIMULATION
Create a new NetworkPolicy named deny-all in the namespace testing which denies all traffic of type ingress and egress traffic
Answer:
Explanation:
You can create a "default" isolation policy for a namespace by creating a NetworkPolicy that selects all pods but does not allow any ingress traffic to those pods.
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: default-deny-ingress
spec:
podSelector: {}
policyTypes:
- Ingress
You can create a "default" egress isolation policy for a namespace by creating a NetworkPolicy that selects all pods but does not allow any egress traffic from those pods.
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: allow-all-egress
spec:
podSelector: {}
egress:
- {}
policyTypes:
- Egress
Default deny all ingress and all egress traffic
You can create a "default" policy for a namespace which prevents all ingress AND egress traffic by creating the following NetworkPolicy in that namespace.
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: default-deny-all
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
This ensures that even pods that aren't selected by any other NetworkPolicy will not be allowed ingress or egress traffic.
NEW QUESTION # 32
On the Cluster worker node, enforce the prepared AppArmor profile
#include <tunables/global>
profile nginx-deny flags=(attach_disconnected) {
#include <abstractions/base>
file,
# Deny all file writes.
deny /** w,
}
EOF'
Edit the prepared manifest file to include the AppArmor profile.
apiVersion: v1
kind: Pod
metadata:
name: apparmor-pod
spec:
containers:
- name: apparmor-pod
image: nginx
Finally, apply the manifests files and create the Pod specified on it.
Verify: Try to make a file inside the directory which is restricted.
Answer:
Explanation:
NEW QUESTION # 33
SIMULATION
On the Cluster worker node, enforce the prepared AppArmor profile
#include <tunables/global>
profile docker-nginx flags=(attach_disconnected,mediate_deleted) {
#include <abstractions/base>
network inet tcp,
network inet udp,
network inet icmp,
deny network raw,
deny network packet,
file,
umount,
deny /bin/** wl,
deny /boot/** wl,
deny /dev/** wl,
deny /etc/** wl,
deny /home/** wl,
deny /lib/** wl,
deny /lib64/** wl,
deny /media/** wl,
deny /mnt/** wl,
deny /opt/** wl,
deny /proc/** wl,
deny /root/** wl,
deny /sbin/** wl,
deny /srv/** wl,
deny /tmp/** wl,
deny /sys/** wl,
deny /usr/** wl,
audit /** w,
/var/run/nginx.pid w,
/usr/sbin/nginx ix,
deny /bin/dash mrwklx,
deny /bin/sh mrwklx,
deny /usr/bin/top mrwklx,
capability chown,
capability dac_override,
capability setuid,
capability setgid,
capability net_bind_service,
deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)
# deny write to files not in /proc/<number>/** or /proc/sys/**
deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w, deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel) deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/ deny @{PROC}/sysrq-trigger rwklx, deny @{PROC}/mem rwklx, deny @{PROC}/kmem rwklx, deny @{PROC}/kcore rwklx, deny mount, deny /sys/[^f]*/** wklx, deny /sys/f[^s]*/** wklx, deny /sys/fs/[^c]*/** wklx, deny /sys/fs/c[^g]*/** wklx, deny /sys/fs/cg[^r]*/** wklx, deny /sys/firmware/** rwklx, deny /sys/kernel/security/** rwklx,
}
Edit the prepared manifest file to include the AppArmor profile.
apiVersion: v1
kind: Pod
metadata:
name: apparmor-pod
spec:
containers:
- name: apparmor-pod
image: nginx
Finally, apply the manifests files and create the Pod specified on it.
Verify: Try to use command ping, top, sh
- A. Send us the Feedback on it.
Answer: A
NEW QUESTION # 34
Create a Pod name Nginx-pod inside the namespace testing, Create a service for the Nginx-pod named nginx-svc, using the ingress of your choice, run the ingress on tls, secure port.
- A. Send us your Feedback on this.
Answer: A
NEW QUESTION # 35
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).
Answer:
Explanation:
NEW QUESTION # 36
Fix all issues via configuration and restart the affected components to ensure the new setting takes effect.
Fix all of the following violations that were found against the API server:- a. Ensure the --authorization-mode argument includes RBAC b. Ensure the --authorization-mode argument includes Node c. Ensure that the --profiling argument is set to false Fix all of the following violations that were found against the Kubelet:- a. Ensure the --anonymous-auth argument is set to false.
b. Ensure that the --authorization-mode argument is set to Webhook.
Fix all of the following violations that were found against the ETCD:-
a. Ensure that the --auto-tls argument is not set to true
Hint: Take the use of Tool Kube-Bench
Answer:
Explanation:
API server:
Ensure the --authorization-mode argument includes RBAC
Turn on Role Based Access Control. Role Based Access Control (RBAC) allows fine-grained control over the operations that different entities can perform on different objects in the cluster. It is recommended to use the RBAC authorization mode.
Fix - Buildtime
Kubernetes
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
component: kube-apiserver
tier: control-plane
name: kube-apiserver
namespace: kube-system
spec:
containers:
- command:
+ - kube-apiserver
+ - --authorization-mode=RBAC,Node
image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
livenessProbe:
failureThreshold: 8
httpGet:
host: 127.0.0.1
path: /healthz
port: 6443
scheme: HTTPS
initialDelaySeconds: 15
timeoutSeconds: 15
name: kube-apiserver-should-pass
resources:
requests:
cpu: 250m
volumeMounts:
- mountPath: /etc/kubernetes/
name: k8s
readOnly: true
- mountPath: /etc/ssl/certs
name: certs
- mountPath: /etc/pki
name: pki
hostNetwork: true
volumes:
- hostPath:
path: /etc/kubernetes
name: k8s
- hostPath:
path: /etc/ssl/certs
name: certs
- hostPath:
path: /etc/pki
name: pki
Ensure the --authorization-mode argument includes Node
Remediation: Edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and set the --authorization-mode parameter to a value that includes Node.
--authorization-mode=Node,RBAC
Audit:
/bin/ps -ef | grep kube-apiserver | grep -v grep
Expected result:
'Node,RBAC' has 'Node'
Ensure that the --profiling argument is set to false
Remediation: Edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and set the below parameter.
--profiling=false
Audit:
/bin/ps -ef | grep kube-apiserver | grep -v grep
Expected result:
'false' is equal to 'false'
Fix all of the following violations that were found against the Kubelet:- Ensure the --anonymous-auth argument is set to false.
Remediation: If using a Kubelet config file, edit the file to set authentication: anonymous: enabled to false. If using executable arguments, edit the kubelet service file /etc/systemd/system/kubelet.service.d/10-kubeadm.conf on each worker node and set the below parameter in KUBELET_SYSTEM_PODS_ARGS variable.
--anonymous-auth=false
Based on your system, restart the kubelet service. For example:
systemctl daemon-reload
systemctl restart kubelet.service
Audit:
/bin/ps -fC kubelet
Audit Config:
/bin/cat /var/lib/kubelet/config.yaml
Expected result:
'false' is equal to 'false'
2) Ensure that the --authorization-mode argument is set to Webhook.
Audit
docker inspect kubelet | jq -e '.[0].Args[] | match("--authorization-mode=Webhook").string' Returned Value: --authorization-mode=Webhook Fix all of the following violations that were found against the ETCD:- a. Ensure that the --auto-tls argument is not set to true Do not use self-signed certificates for TLS. etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive in nature and should not be available to unauthenticated clients. You should enable the client authentication via valid certificates to secure the access to the etcd service.
Fix - Buildtime
Kubernetes
apiVersion: v1
kind: Pod
metadata:
annotations:
scheduler.alpha.kubernetes.io/critical-pod: ""
creationTimestamp: null
labels:
component: etcd
tier: control-plane
name: etcd
namespace: kube-system
spec:
containers:
- command:
+ - etcd
+ - --auto-tls=true
image: k8s.gcr.io/etcd-amd64:3.2.18
imagePullPolicy: IfNotPresent
livenessProbe:
exec:
command:
- /bin/sh
- -ec
- ETCDCTL_API=3 etcdctl --endpoints=https://[192.168.22.9]:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt
--cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key=/etc/kubernetes/pki/etcd/healthcheck-client.key get foo failureThreshold: 8 initialDelaySeconds: 15 timeoutSeconds: 15 name: etcd-should-fail resources: {} volumeMounts:
- mountPath: /var/lib/etcd
name: etcd-data
- mountPath: /etc/kubernetes/pki/etcd
name: etcd-certs
hostNetwork: true
priorityClassName: system-cluster-critical
volumes:
- hostPath:
path: /var/lib/etcd
type: DirectoryOrCreate
name: etcd-data
- hostPath:
path: /etc/kubernetes/pki/etcd
type: DirectoryOrCreate
name: etcd-certs
status: {}
Explanation:
NEW QUESTION # 37
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.
Answer:
Explanation:
NEW QUESTION # 38
SIMULATION
Create a RuntimeClass named untrusted using the prepared runtime handler named runsc.
Create a Pods of image alpine:3.13.2 in the Namespace default to run on the gVisor runtime class.
Verify: Exec the pods and run the dmesg, you will see output like this:-
- A. Send us your feedback on it.
Answer: A
NEW QUESTION # 39
Cluster: dev
Master node: master1
Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context dev
Task:
Retrieve the content of the existing secret named adam in the safe namespace.
Store the username field in a file names /home/cert-masters/username.txt, and the password field in a file named /home/cert-masters/password.txt.
1. You must create both files; they don't exist yet.
2. Do not use/modify the created files in the following steps, create new temporary files if needed.
Create a new secret names newsecret in the safe namespace, with the following content:
Username: dbadmin
Password: moresecurepas
Finally, create a new Pod that has access to the secret newsecret via a volume:
Namespace: safe
Pod name: mysecret-pod
Container name: db-container
Image: redis
Volume name: secret-vol
Mount path: /etc/mysecret
Answer:
Explanation:
1. Get the secret, decrypt it & save in files
k get secret adam -n safe -o yaml
2. Create new secret using --from-literal
[desk@cli] $k create secret generic newsecret -n safe --from-literal=username=dbadmin --from-literal=password=moresecurepass
3. Mount it as volume of db-container of mysecret-pod
Explanation
[desk@cli] $k create secret generic newsecret -n safe --from-literal=username=dbadmin --from-literal=password=moresecurepass secret/newsecret created
[desk@cli] $vim /home/certs_masters/secret-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: mysecret-pod
namespace: safe
labels:
run: mysecret-pod
spec:
containers:
- name: db-container
image: redis
volumeMounts:
- name: secret-vol
mountPath: /etc/mysecret
readOnly: true
volumes:
- name: secret-vol
secret:
secretName: newsecret
[desk@cli] $ k apply -f /home/certs_masters/secret-pod.yaml
pod/mysecret-pod created
[desk@cli] $ k exec -it mysecret-pod -n safe - cat /etc/mysecret/username dbadmin
[desk@cli] $ k exec -it mysecret-pod -n safe - cat /etc/mysecret/password moresecurepas
NEW QUESTION # 40
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context qa
Context:
A pod fails to run because of an incorrectly specified ServiceAccount
Task:
Create a new service account named backend-qa in an existing namespace qa, which must not have access to any secret.
Edit the frontend pod yaml to use backend-qa service account
Note: You can find the frontend pod yaml at /home/cert_masters/frontend-pod.yaml
Answer:
Explanation:
[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/ pod/frontend created
[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/
NEW QUESTION # 41
......
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