Linux Foundation Updated CKA Exam Questions and Answers by zaynab

Task Summary

You are given a host to prepare for Kubernetes:

Use dpkg to install cri-dockerd

Enable and start the cri-docker service

Set net.bridge.bridge-nf-call-iptables to 1 via sysctl

Step-by-Step Instructions

1️⃣ SSH into the correct node

bash

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ssh cka000051

⚠️ Required — failure to connect to the correct host = zero score.

2️⃣ Install cri-dockerd

You are told the .deb file is already located at:

bash

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~/cri-dockerd_0.3.9.3-0.ubuntu-jammy_amd64.deb

Install it with dpkg:

bash

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sudo dpkg -i ~/cri-dockerd_0.3.9.3-0.ubuntu-jammy_amd64.deb

???? If any dependencies are missing (e.g., golang or containerd), you might need:

bash

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sudo apt-get install -f -y

But usually, the exam system provides a pre-validated .deb environment.

3️⃣ Enable and start cri-docker service

Start and enable both services:

bash

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sudo systemctl enable cri-docker.service

sudo systemctl enable --now cri-docker.socket

sudo systemctl start cri-docker.service

Check status (optional but smart):

bash

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sudo systemctl status cri-docker.service

You should see it active (running).

4️⃣ Configure the sysctl parameter

Set net.bridge.bridge-nf-call-iptables=1 immediately and persistently.

Step A: Apply immediately:

sudo sysctl net.bridge.bridge-nf-call-iptables=1

Step B: Persist it in /etc/sysctl.d:

Create or modify a file:

echo "net.bridge.bridge-nf-call-iptables = 1" | sudo tee /etc/sysctl.d/k8s.conf

Reload sysctl:

sudo sysctl --system

Verify:

sysctl net.bridge.bridge-nf-call-iptables

Should return:

net.bridge.bridge-nf-call-iptables = 1

✅ Now the system is ready for kubeadm with Docker (via cri-dockerd)!

ssh cka000051

sudo dpkg -i ~/cri-dockerd_0.3.9.3-0.ubuntu-jammy_amd64.deb

sudo systemctl enable cri-docker.service

sudo systemctl enable --now cri-docker.socket

sudo systemctl start cri-docker.service

sudo sysctl net.bridge.bridge-nf-call-iptables=1

echo "net.bridge.bridge-nf-call-iptables = 1" | sudo tee /etc/sysctl.d/k8s.conf

sudo sysctl --system

Task Summary

SSH into cka000054

Install a CNI plugin that supports NetworkPolicies

Two CNI options provided:

Flannel v0.26.1 (❌ does NOT support NetworkPolicies)

Calico v3.28.2 ✅ (does support NetworkPolicies)

❗ Decision Point: Which CNI to choose?

✅ Choose Calico, because only Calico supports enforcing NetworkPolicies natively. Flannel does not.

✅ Step-by-Step Solution

1️⃣ SSH into the correct node

ssh cka000054

⚠️ Required. Skipping this results in zero score.

2️⃣ Install Calico CNI (v3.28.2)

Use the official manifest provided:

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.28.2/manifests/tigera-operator.yaml

This installs the Calico Operator, which then deploys the full Calico CNI stack.

3️⃣ Wait for Calico components to come up

Check the pods in tigera-operator and calico-system namespaces:

kubectl get pods -n tigera-operator

kubectl get pods -n calico-system

✅ You should see pods like:

calico-kube-controllers

calico-node

calico-typha

tigera-operator

Wait for all to be in Running state.

✅ (Optional) 4️⃣ Confirm CNI is enforcing NetworkPolicies

You can check:

kubectl get crds | grep networkpolicy

You should see:

networkpolicies.crd.projectcalico.org

This confirms Calico's CRDs are installed for policy enforcement.

Final Command Summary

ssh cka000054

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.28.2/manifests/tigera-operator.yaml

kubectl get pods -n tigera-operator

kubectl get pods -n calico-system

kubectl get crds | grep networkpolicy

Task Summary

You need to:

SSH into the correct node: cka000055

Use kubectl to list all cert-manager CRDs, and save that list to ~/resources.yaml

Do not use any output format flags like -o yaml

Extract the documentation for the spec.subject field of the Certificate custom resource and save it to ~/subject.yaml

Step-by-Step Instructions

Step 1: SSH into the node

ssh cka000055

Step 2: List cert-manager CRDs and save to a file

First, identify all cert-manager CRDs:

kubectl get crds | grep cert-manager

Then extract them without specifying an output format:

kubectl get crds | grep cert-manager | awk '{print $1}' | xargs kubectl get crd > ~/resources.yaml

This saves the default kubectl get output to the required file without formatting flags.

Step 3: Get documentation for spec.subject in the Certificate CRD

Run the following command:

kubectl explain certificate.spec.subject > ~/subject.yaml

This extracts the field documentation and saves it to the specified file.

If you're not sure of the resource, verify it exists:

kubectl get crd certificates.cert-manager.io

Final Command Summary

ssh cka000055

kubectl get crds | grep cert-manager | awk '{print $1}' | xargs kubectl get crd > ~/resources.yaml

kubectl explain certificate.spec.subject > ~/subject.yaml

Solution:

kubectl top -l name=cpu-user -A

echo 'pod name' >> /opt/KUT00401/KUT00401.txt