Road to Kubestronaut: How I Passed CKA on My First Attempt

The Certified Kubernetes Administrator (CKA) was my first step toward becoming a Golden Kubestronaut — a title awarded to engineers who complete all 11 CNCF Kubernetes certifications. I passed on my first attempt with a score of 79% (passing threshold: 66%).

Here’s everything I actually did to prepare.

My Background

At the time I took CKA, I had been working as a Cloud Engineer at NAB for about 3 years, primarily focused on AWS and FinOps. I had hands-on Kubernetes experience from production workloads, but I had never formally studied the spec.

Preparation: 2 Months, 2 Resources Only

I kept it simple. I used exactly two resources:

1. KodeKloud CKA Course

KodeKloud is the best structured course for CKA. The labs are realistic, the explanations are clear, and it covers every domain on the exam curriculum. I went through the entire course once, doing every lab.

What I liked:

  • Hands-on labs after every section
  • Mock exams with timed conditions
  • Covers edge cases you won’t find in the docs

2. Killercoda

After finishing KodeKloud, I used Killercoda for extra practice on specific scenarios — especially troubleshooting. Killercoda scenarios are community-contributed and often more creative than KodeKloud labs.

I focused on:

  • ETCD backup and restore
  • Node troubleshooting
  • Network policy scenarios

I did not use: books, YouTube videos, or blog posts for preparation. Two focused resources beat ten scattered ones.

The Exam: What’s Actually Hard

The CKA is a performance-based exam — you work in a live Kubernetes cluster, not multiple choice. You have 2 hours for ~17 tasks.

Hardest sections (in my experience):

1. Troubleshooting This is where most people lose points. The cluster is broken — you need to find out why. Common scenarios:

  • kubelet not running on a node
  • Wrong kubeconfig
  • Broken network plugin
  • Pod stuck in Pending/CrashLoopBackOff

The key skill: read logs systematically. Start with kubectl describe, then journalctl -u kubelet, then component logs.

2. Cluster Upgrade Upgrading kubeadm, kubelet, and kubectl in the correct order under time pressure is stressful. Practice this until it’s muscle memory:

# Control plane
kubeadm upgrade plan
kubeadm upgrade apply v1.x.x
apt-mark unhold kubelet kubectl
apt-get install kubelet=1.x.x-00 kubectl=1.x.x-00
apt-mark hold kubelet kubectl
systemctl restart kubelet

# Worker node
kubectl drain <node> --ignore-daemonsets
# SSH into node, repeat kubelet/kubectl upgrade
kubectl uncordon <node>

My #1 Tip: Always Use -o yaml Instead of Imperative Updates

This is the single most important habit for the CKA exam.

Don’t do this:

kubectl set image deployment/nginx nginx=nginx:1.19

Do this instead:

kubectl get deployment nginx -o yaml > nginx.yaml
# edit the file
kubectl apply -f nginx.yaml

Why? Because:

  • You can see the full spec before applying — fewer mistakes
  • Easier to make multiple changes at once
  • If something breaks, you have the original YAML to reference
  • The exam environment sometimes has unexpected cluster states — editing YAML gives you full control

The only exception: generating initial resource YAML with --dry-run=client -o yaml:

kubectl create deployment nginx --image=nginx --dry-run=client -o yaml > deployment.yaml

Exam Day Tips

Set up aliases immediately (first 2 minutes of the exam):

alias k=kubectl
export do="--dry-run=client -o yaml"
export now="--grace-period=0 --force"

Use the right namespace. Every task specifies a namespace. Always check:

kubectl config set-context --current --namespace=<namespace>

Don’t get stuck. If a task is taking too long, flag it and move on. You can always come back. A 4% task isn’t worth 15 minutes.

Use kubectl explain. The docs are available during the exam, but kubectl explain is faster for finding field names:

kubectl explain pod.spec.containers.resources

Result

Score: 79% | Passing: 66% | Result: PASS ✅

First attempt. The troubleshooting section was the tightest — I flagged 2 tasks and came back to them. The cluster upgrade went smoothly because I had practiced it many times.

What’s Next on the Road to Kubestronaut

CKA is just the beginning. The full Kubestronaut path requires:

  • ✅ CKA (Certified Kubernetes Administrator)
  • ⬜ CKAD (Certified Kubernetes Application Developer)
  • ⬜ CKS (Certified Kubernetes Security Specialist)
  • ⬜ KCNA (Kubernetes and Cloud Native Associate)
  • ⬜ KCSA (Kubernetes and Cloud Native Security Associate)
  • ⬜ …and 6 more CNCF certifications

I’ll cover each one in this series. Follow along if you’re on the same path.

Questions about CKA prep? Connect with me on LinkedIn or check my full cert list on Credly.