Achieve the CKS Exam Best Results with Help from Linux Foundation Certified Experts [Q17-Q38]

QUESTION 17
Create a network policy named restrict-np to restrict to pod nginx-test running in namespace testing.
Only allow the following Pods to connect to Pod nginx-test:-
1. pods in the namespace default
2. pods with label version:v1 in any namespace.
Make sure to apply the network policy.

QUESTION 18
You must complete this task on the following cluster/nodes: Cluster: immutable-cluster Master node: master1 Worker node: worker1 You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context immutable-cluster Context: It is best practice to design containers to be stateless and immutable. Task: Inspect Pods running in namespace prod and delete any Pod that is either not stateless or not immutable. Use the following strict interpretation of stateless and immutable: 1. Pods being able to store data inside containers must be treated as not stateless. Note: You don’t have to worry whether data is actually stored inside containers or not already. 2. Pods being configured to be privileged in any way must be treated as potentially not stateless or not immutable.

QUESTION 19
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’

QUESTION 20
SIMULATION
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.

QUESTION 21
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.

QUESTION 22
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

QUESTION 23
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

QUESTION 24
SIMULATION
Using the runtime detection tool Falco, Analyse the container behavior for at least 30 seconds, using filters that detect newly spawning and executing processes store the incident file art /opt/falco-incident.txt, containing the detected incidents. one per line, in the format
[timestamp],[uid],[user-name],[processName]

QUESTION 25
Context
A default-deny NetworkPolicy avoids to accidentally expose a Pod in a namespace that doesn’t have any other NetworkPolicy defined.
Task
Create a new default-deny NetworkPolicy named defaultdeny in the namespace testing for all traffic of type Egress.
The new NetworkPolicy must deny all Egress traffic in the namespace testing.
Apply the newly created default-deny NetworkPolicy to all Pods running in namespace testing.

QUESTION 26
SIMULATION
Use the kubesec docker images to scan the given YAML manifest, edit and apply the advised changes, and passed with a score of 4 points.
kubesec-test.yaml
apiVersion: v1
kind: Pod
metadata:
name: kubesec-demo
spec:
containers:
– name: kubesec-demo
image: gcr.io/google-samples/node-hello:1.0
securityContext:
readOnlyRootFilesystem: true
Hint: docker run -i kubesec/kubesec:512c5e0 scan /dev/stdin < kubesec-test.yaml

QUESTION 27
Enable audit logs in the cluster, To Do so, enable the log backend, and ensure that
1. logs are stored at /var/log/kubernetes/kubernetes-logs.txt.
2. Log files are retained for 5 days.
3. at maximum, a number of 10 old audit logs files are retained.
Edit and extend the basic policy to log:
1. Cronjobs changes at RequestResponse
2. Log the request body of deployments changes in the namespace kube-system.
3. Log all other resources in core and extensions at the Request level.
4. Don’t log watch requests by the “system:kube-proxy” on endpoints or

QUESTION 28
You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context dev Context: A CIS Benchmark tool was run against the kubeadm created cluster and found multiple issues that must be addressed. Task: Fix all issues via configuration and restart the affected components to ensure the new settings take effect. Fix all of the following violations that were found against the API server: 1.2.7 authorization-mode argument is not set to AlwaysAllow FAIL 1.2.8 authorization-mode argument includes Node FAIL 1.2.7 authorization-mode argument includes RBAC FAIL Fix all of the following violations that were found against the Kubelet: 4.2.1 Ensure that the anonymous-auth argument is set to false FAIL 4.2.2 authorization-mode argument is not set to AlwaysAllow FAIL (Use Webhook autumn/authz where possible) Fix all of the following violations that were found against etcd: 2.2 Ensure that the client-cert-auth argument is set to true

QUESTION 29
You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context prod-account Context: A Role bound to a Pod’s ServiceAccount grants overly permissive permissions. Complete the following tasks to reduce the set of permissions. Task: Given an existing Pod named web-pod running in the namespace database. 1. Edit the existing Role bound to the Pod’s ServiceAccount test-sa to only allow performing get operations, only on resources of type Pods. 2. Create a new Role named test-role-2 in the namespace database, which only allows performing update operations, only on resources of type statuefulsets. 3. Create a new RoleBinding named test-role-2-bind binding the newly created Role to the Pod’s ServiceAccount. Note: Don’t delete the existing RoleBinding.

QUESTION 30
Create a new NetworkPolicy named deny-all in the namespace testing which denies all traffic of type ingress and egress traffic

QUESTION 31
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.

QUESTION 32
Enable audit logs in the cluster, To Do so, enable the log backend, and ensure that
1. logs are stored at /var/log/kubernetes/kubernetes-logs.txt.
2. Log files are retained for 5 days.
3. at maximum, a number of 10 old audit logs files are retained.
Edit and extend the basic policy to log:

QUESTION 33
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

QUESTION 34
SIMULATION
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

QUESTION 35
You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context stage Context: A PodSecurityPolicy shall prevent the creation of privileged Pods in a specific namespace. Task: 1. Create a new PodSecurityPolcy named deny-policy, which prevents the creation of privileged Pods. 2. Create a new ClusterRole name deny-access-role, which uses the newly created PodSecurityPolicy deny-policy. 3. Create a new ServiceAccount named psd-denial-sa in the existing namespace development. Finally, create a new ClusterRoleBindind named restrict-access-bind, which binds the newly created ClusterRole deny-access-role to the newly created ServiceAccount psp-denial-sa

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

QUESTION 37
Analyze and edit the given Dockerfile
FROM ubuntu:latest
RUN apt-get update -y
RUN apt-install nginx -y
COPY entrypoint.sh /
ENTRYPOINT [“/entrypoint.sh”]
USER ROOT
Fixing two instructions present in the file being prominent security best practice issues Analyze and edit the deployment manifest file apiVersion: v1 kind: Pod metadata:
name: security-context-demo-2
spec:
securityContext:
runAsUser: 1000
containers:
– name: sec-ctx-demo-2
image: gcr.io/google-samples/node-hello:1.0
securityContext:
runAsUser: 0
privileged: True
allowPrivilegeEscalation: false
Fixing two fields present in the file being prominent security best practice issues Don’t add or remove configuration settings; only modify the existing configuration settings Whenever you need an unprivileged user for any of the tasks, use user test-user with the user id 5487

QUESTION 38
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