CKAD Certification Snippets

Fri, 22 Aug 2025 00:00:00 +0200

Introduction

The Certified Kubernetes Application Developer (CKAD) exam is a hands-on, command-line-heavy challenge that tests your ability to design, build, and deploy applications in Kubernetes - all while racing the clock.

I recently took the CKAD and passed with an overall score of around 82%. Not perfect - but let’s be honest, in a terminal-only, time-boxed environment, "running" is the new "succeeding" 😄.

This article collects the practical snippets, workflows, and quick references I used during my preparation.

Install Kubernetes Components - Kubeadm, Kubectl, Kubelet

Fri, 14 May 2021 00:00:00 +0200

Goals

Install kubeadm, kubectl and kubelet on Debian-based Linux
Freeze their versions to avoid automatic updates

Installation

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - (1)

cat << EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list (2)
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

sudo apt-get update (3)

sudo apt-get install -y kubelet=1.15.7-00 kubeadm=1.15.7-00 kubectl=1.15.7-00 (4)

sudo apt-mark hold kubelet kubeadm kubectl (5)

1 Add the GPG key

2 Add the kubernetes repo to the sources list

3 Update the index

Install kubelet, kubeadm and kubectl

It’s important to use the same version for kubelet, kubeadm and kubectl.

Setting up a Kubernetes Master Node

Fri, 14 May 2021 00:00:00 +0200

Goals

Setup a kubernetes master node on a Linux machine

Setup

Initialize the cluster on the master node

sudo kubeadm init --pod-network-cidr=10.244.0.0/16

This might take a few minutes … afterward we set up our local kubeconfig:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Verify the Cluster Setup

Shows that the cluster is responding and kubectl working:

kubectl version

Kubernetes Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Fetch and Decode Secret

You need to have jq installed to use this snippet!

kubectl --context=my-context -n my-namespace get secret my-secret-name -o json | jq '.data | map_values(@base64d)'

Rerun existing completed Job

kubectl replace deletes the old job, if there is any error, your job definition is lost, don’t forget to save it first!

Replace an existing Job with itself

kubectl get job JOBNAME -o yaml | kubectl replace --force -f -

Kubectl on Micha Kops' Tech Notes