If you’ve been preparing for a Kubernetes certification, you already know the biggest challenge isn’t learning the concepts — it’s getting enough hands-on practice in a realistic exam environment. Textbooks and video courses can only take you so far. When exam day arrives, you’re sitting in front of a real terminal, a real cluster, and a ticking clock.
That’s exactly why we built CK-X — a completely free, open-source Kubernetes exam simulator that runs real clusters on your local machine.
What is CK-X?
CK-X is an open-source exam simulation platform that replicates the actual Kubernetes certification exam experience. It supports all three performance-based CNCF certifications:
- CKA — Certified Kubernetes Administrator
- CKAD — Certified Kubernetes Application Developer
- CKS — Certified Kubernetes Security Specialist
Unlike flashcard apps or multiple-choice quizzes, CK-X gives you a real Kubernetes cluster to work with. You solve tasks in a web-based terminal, just like the actual exam, complete with a countdown timer and automated scoring.
Why CK-X is Different
Most exam prep tools offer one of two things: theory-based quizzes or expensive cloud labs. CK-X takes a different approach:
Real Kubernetes Clusters
CK-X uses K3D (lightweight K3s in Docker) to spin up actual Kubernetes clusters on your machine. Every kubectl command you run hits a real API server. No mocks, no simulations — real clusters.
Exam-Realistic Interface
The web-based interface includes a remote desktop and a remote terminal, mimicking the PSI exam environment you’ll encounter on test day. This matters more than most people realize — familiarity with the interface can save you precious minutes.
Automated Validation
After completing each task, CK-X runs validation scripts against your cluster to verify your solutions. You get immediate feedback on what you got right and what needs work.
Timed Exam Mode
Practice under pressure with a configurable countdown timer. Time management is one of the most critical — and most overlooked — skills for Kubernetes exams.
Getting Started in Under 5 Minutes
CK-X runs entirely in Docker, so setup is straightforward.
Prerequisites:
- Docker Desktop or Docker Engine installed
- Minimum 4GB RAM (8GB recommended)
- 10GB free disk space
Install on Linux/macOS:
curl -fsSL https://raw.githubusercontent.com/sailor-sh/CK-X/master/scripts/install.sh | bashInstall on Windows (PowerShell as Admin, WSL2 required):
irm https://raw.githubusercontent.com/sailor-sh/CK-X/master/scripts/install.ps1 | iexOr clone and run manually:
git clone https://github.com/sailor-sh/CK-X.git
cd CK-X
docker compose up -dOnce running, open http://localhost:30080 in your browser. That’s it — you’re ready to practice.
How CK-X Works Under the Hood
CK-X runs 8 Docker services that work together to create a complete exam environment:
| Component | What It Does |
|---|---|
| K8s API Server | Runs the actual K3D Kubernetes cluster |
| Remote Desktop | Web-based VNC desktop, just like the real exam |
| Remote Terminal | SSH-based terminal for cluster access |
| Web App | Main interface for selecting and taking exams |
| Facilitator | Manages lab setup, validation, and scoring |
| Jump Host | SSH access point to the cluster nodes |
| Nginx | Reverse proxy (only exposed port: 30080) |
| Redis | Session and state management |
All of this runs locally on your machine. No cloud account needed, no subscription required.
Making the Most of CK-X
Here’s how to get maximum value from your CK-X practice sessions:
1. Start with Untimed Practice
Before turning on the timer, work through each lab without time pressure. Focus on understanding the commands and the reasoning behind each step.
2. Review the Validation Scripts
After solving a task, look at the validation scripts in the facilitator/assets/exams/ directory. Understanding what the validator checks helps you learn exactly what the exam expects.
3. Repeat Until Automatic
The goal isn’t just to solve each problem once — it’s to solve them fast enough that you have time to spare on exam day. Repeat labs until the commands feel automatic.
4. Simulate Real Exam Conditions
When you’re ready, do a full timed run. Close all notes and documentation except the official Kubernetes docs (which you’re allowed to use in the real exam). This is the closest you’ll get to the real thing without actually sitting for the exam.
When You’re Ready for More
CK-X gives you a solid foundation for hands-on practice, and it’s a great starting point for any Kubernetes certification journey. But as you progress, you might find yourself wanting more — more questions, more variety, more detailed feedback on where you’re struggling.
That’s where our exam-ready mock bundles come in. Built by the same team behind CK-X, these bundles offer a much larger question bank, AI-powered performance analysis, and practice exams that closely mirror the real exam difficulty:
- CKA Mock Exam Bundle — Comprehensive practice for the Certified Kubernetes Administrator exam
- CKAD Mock Exam Bundle — Focused practice for the Application Developer certification
- CKS Mock Exam Bundle — Deep security-focused exam preparation
- KubeAstronaut Bundle — For those pursuing all Kubernetes certifications
Contributing to CK-X
CK-X is open source under the MIT license, and we welcome contributions. Whether it’s new exam labs, bug fixes, or documentation improvements — every contribution helps the community.
Check out the contributing guide on GitHub to get started. If you’ve recently passed a certification and want to help others prepare, contributing new practice labs is one of the most impactful things you can do.
Conclusion
Preparing for Kubernetes certifications doesn’t have to be expensive. CK-X gives you a free, realistic exam environment that you can run on your own machine, as many times as you need. Combine it with consistent study habits and the right resources, and you’ll walk into your exam with confidence.
Give CK-X a try — clone the repo, spin it up, and start practicing today.