Certifications

Several certifications available 🔗

The CNCF delivers several Kubernetes certifications, which are listed in the following table.

If you pass all those certifications, you become a https://www.cncf.io/training/kubestronaut/.

Expectation for the CKA 🔗

The following table summarizes the distribution of the CKA questions across 5 main subjects.

CKA Environment 🔗

The CKA is a 2h exam. It contains 15/20 questions and requires at least 66% correct answers. This exam is remotely proctored, so you can take it from home (or any other quiet location) at a time that best suits your schedule.

Before launching the exam, which you do via your Linux Foundation Training Portal, you need to perform a couple of prerequisites including making sure the PSI Browser works correctly on your environment. This browser gives you access to the remote Desktop you’ll use during the exam.

Tips & tricks 🔗

Tools 🔗

Make sure you have a basic knowledge of

• vi/vim

As this editor is available on almost all Linux distributions, knowing the basic commands is important to be able to create/edit a file quickly.

• openssl

The following command can be useful to verify the content of a certificate.

openssl x509 -in cert.crt -noout -text

• systemd / systemctl / journalctl

systemd related commands are useful to start/restart/stop and get the logs of processes.

# Restart kubelet
systemctl restart kubelet

# Check kubelet logs
journalctl -u kubelet

• sysctl

You may need this tool to change ipv4 forwarding or other networking things

# Check is ipv4 forwarding is enabled
sysctl net.ipv4.ip_forward

# Enable ipv4 forwarding
sysctl -w net.ipv4.ip_forward=1

# Disable ipv4 forwarding
sysctl -w net.ipv4.ip_forward=0

• dpkg

During the exam you may be requested to install a package from its .deb file

sudo dpkg -i my-package.deb

• crictl

crictl is a command-line interface for CRI-compatible container runtimes. It can be used to inspect and debug container runtimes and applications (pods / containers) on a Kubernetes node. During the exam, you may be asked to install crictl.

wget https://github.com/kubernetes-sigs/cri-tools/releases/download/v1.33.0/crictl-v1.33.0-linux-amd64.tar.gz
tar xvf crictl-v1.33.0-linux-amd64.tar.gz 
sudo mv crictl /usr/local/bin/

Aliases 🔗

Definiing a couple of aliases at the very beginning of the examination could save time.

alias k=kubectl
export dr=”--dry-run=client -o yaml”
export fd=”--grace-period=0 --force”

Imperative commands 🔗

Don’t create specifications manually, instead use --dry-run=client -o yaml as in these examples.

k run nginx --image=nginx:1.20 --dry-run=client -o yaml > pod.yaml
k create deploy www --image=nginx:1.20 --replicas=3 --dry-run=client -o yaml > deploy.yaml
k create role create-pod --verb=create --resource=pods --dry-run=client -o yaml > role.yaml

Quickly change the current Namespace.

k config set-context --current --namespace=dev

Don’t wait for the grace period to get rid of a Pod.

k delete po nginx --force --grace-period=0

Reference guide 🔗

The Kubectl quick reference guide is a must-read.

Access to am exam simulator 🔗

Registering for the CKA gives you access to two sessions of the official Exam simulator. I hightly recommend using these sessions once you’re almost ready.