A Beginner’s Guide to the CKS Exam Domains

Table of Contents

• What is the CKS Exam?
• Overview of the CKS Exam
• Domain 1: Cluster Setup (15%)
• Domain 2: Cluster Hardening (15%)
• Domain 3: System Hardening (10%)
• Domain 4: Minimize Microservice Vulnerabilities (20%)
• Domain 5: Supply Chain Security (20%)
• Domain 6: Monitoring, Logging, and Runtime Security (20%)
• Preparation Tips for Beginners
• Conclusion
• FAQs

What is the CKS Exam?

The CKS, or Certified Kubernetes Security Specialist, is a certification from the Cloud Native Computing Foundation (CNCF) and the Linux Foundation. It's all about proving you can secure Kubernetes clusters—the groups of machines that run your containerized apps. Think of Kubernetes as the manager that orchestrates where and how your apps run, scaling them up or down as needed.

Why bother with CKS? In 2025, with cyber attacks hitting headlines weekly, companies need experts who can protect their cloud setups. This exam isn't multiple-choice; it's hands-on. You'll log into a simulated cluster and fix security issues using commands. It's intermediate level, so it's perfect if you've got some Kubernetes experience but want to specialize in security. Passing shows employers you're serious about keeping data safe in dynamic environments.

The exam tests real-world skills, like spotting vulnerabilities and applying fixes. It's valid for two years, and as Kubernetes evolves (we're on version 1.33 now), the test updates to match. If you're a beginner, don't worry—we'll unpack each domain simply, explaining why it matters and how to approach it.

Overview of the CKS Exam

Before diving into domains, let's get the big picture. The CKS exam lasts two hours and has about 15-20 tasks. You need 67% to pass, and it costs around $445, including a retake. It's proctored online, so you'll need a quiet space and a webcam.

The curriculum splits into six domains, each with a weight showing its importance. Higher weights mean more questions there. Here's a summary table to visualize:

This table gives you a quick reference. Now, let's explore each domain in detail, with explanations tailored for beginners.

Domain 1: Cluster Setup (15%)

Starting with the foundation: Cluster Setup is about getting your Kubernetes cluster secure from the get-go. Imagine building a house—you want strong locks on the doors before moving in. This domain covers initial configurations to prevent unauthorized access.

One key subtopic is using network security policies. These are like traffic rules for your cluster, deciding who can talk to whom. For example, you might block all traffic except from trusted sources, reducing the chance of lateral movement by hackers.

Next, CIS benchmarks. CIS stands for Center for Internet Security, and their benchmarks are checklists for secure setups. You'll check components like etcd (the cluster's database) or kubelet (the agent on each node) against these standards using tools like kube-bench. It's like a home inspection for security flaws.

Setting up Ingress with TLS is another big one. Ingress is the entry point for external traffic, and TLS (Transport Layer Security) encrypts it, like HTTPS for websites. Without it, data could be snooped on.

Protecting node metadata and endpoints means shielding info about your servers from prying eyes. And verifying platform binaries? That's checking the software files you install aren't tampered with—think scanning for viruses before running a program.

For beginners, start by practicing these in a local setup like Minikube. Understand why each step matters: a weak setup can lead to breaches. This domain is 15%, so expect a few tasks here, like applying a network policy.

Why is this important? In real life, many attacks exploit poor initial configs. By mastering this, you're building a solid base, making the rest of security easier. Take time to experiment—try breaking things safely to see what happens.

Domain 2: Cluster Hardening (15%)

Once set up, it's time to toughen up the cluster— that's Cluster Hardening. Think of it as adding alarms and reinforced doors to your house.

Role-Based Access Control (RBAC) is central here. RBAC assigns permissions like keys to specific rooms. You give users only what they need, minimizing damage if credentials are stolen.

Service accounts are automated users for apps. The advice is to disable defaults and limit new ones' powers—don't give a robot full house access if it only needs the kitchen.

Restricting Kubernetes API access is like guarding the control panel. Only authorized folks should command the cluster.

Upgrading Kubernetes regularly patches holes, as old versions have known vulnerabilities. It's like updating your phone's OS for security fixes.

As a beginner, practice creating RBAC roles with kubectl commands. This domain ties into others, so understanding it helps overall. It's 15%, balanced with setup.

In practice, poor hardening leads to privilege escalation attacks. By focusing here, you'll learn to create least-privilege environments, a key security principle. Don't rush—build simple clusters and harden them step by step.

Domain 3: System Hardening (10%)

System Hardening zooms out to the underlying machines. It's the smallest domain at 10%, but crucial—like securing the land your house is on.

Minimizing the host OS footprint means stripping unnecessary software from servers, reducing "attack surface" (places hackers can target).

Least-privilege IAM (Identity and Access Management) ensures accounts have minimal rights, similar to RBAC but for the OS.

Minimizing external network access blocks unneeded ports, like closing windows you don't use.

Kernel hardening tools like AppArmor or seccomp restrict what programs can do. AppArmor profiles limit file access; seccomp filters system calls. They're like sandboxes for processes.

For newbies, this might seem OS-heavy, but focus on Kubernetes contexts. Practice on virtual machines. Though small, ignore it at your peril—host breaches can compromise the whole cluster.

This domain emphasizes defense in depth. Combine it with others for full protection. Start with basic configs and build up.

Domain 4: Minimize Microservice Vulnerabilities (20%)

Now we get to apps themselves: Minimize Microservice Vulnerabilities, at 20% a heavy hitter. Microservices are small, independent app parts in containers.

Pod security standards are rules for pods (container groups). They enforce things like no root access, preventing escalation.

Managing secrets: Secrets store sensitive info like passwords securely, not in plain code.

Isolation techniques include multi-tenancy (sharing clusters safely) and sandboxed containers (extra isolation layers).

Pod-to-Pod encryption secures internal traffic using tools like Cilium (networking plugin) or Istio (service mesh).

Beginners, think of this as app-level security. Practice creating secure pods. High weight means more tasks—expect scenarios like encrypting traffic.

Why care? Vulnerable microservices are common entry points. This domain teaches shifting security left, into development. Experiment with tools; it's rewarding when you see encrypted comms work.

Domain 5: Supply Chain Security (20%)

Supply Chain Security, another 20%, looks at where your code comes from. Like checking food sources for safety.

Minimize base image footprint: Use slim container bases without extras.

Understand supply chain: Know SBOM (Software Bill of Materials—a component list), CI/CD pipelines, repos.

Secure it: Use trusted registries, sign images (like digital signatures), validate them.

Static analysis: Scan images/workloads for issues with Kubesec or KubeLinter.

For beginners, this is about preventing tainted software. Practice scanning with Trivy. High importance due to recent attacks.

This domain promotes trust in your pipeline. Integrate scans early. It's evolving, so stay updated.

Domain 6: Monitoring, Logging, and Runtime Security (20%)

Finally, Monitoring, Logging, and Runtime Security—watching for trouble while running, 20%.

Behavioral analytics: Spot odd patterns, like unusual file access.

Detect threats across everything: infra, apps, etc.

Investigate attacks: Identify stages (e.g., reconnaissance) and culprits.

Container immutability: Prevent runtime changes.

Audit logs: Track API calls for monitoring.

Beginners, use tools like Falco for runtime. Practice log analysis.

This is detective work. Crucial for response. High weight reflects need for ongoing vigilance.

Preparation Tips for Beginners

To wrap up before conclusion, some tips: Get CKA first. Use labs like Minikube. Study official docs. Practice with simulators. Join communities. Allocate time by weights. Stay calm—it's learnable.

Conclusion

We've journeyed through the CKS exam domains, from setup to runtime security. Each builds a layer of protection, essential in 2025's threat landscape. For beginners, remember: start simple, practice hands-on, and understand the 'why'. CKS isn't just a cert—it's skills for real-world security. Dive in, and you'll emerge ready to safeguard Kubernetes worlds.

FAQs

What are the main domains in the CKS exam?

The exam has six domains: Cluster Setup (15%), Cluster Hardening (15%), System Hardening (10%), Minimize Microservice Vulnerabilities (20%), Supply Chain Security (20%), and Monitoring, Logging, and Runtime Security (20%).

Do I need prior certification for CKS?

Yes, you must pass the Certified Kubernetes Administrator (CKA) exam first.

How long is the CKS exam?

The exam is 2 hours long.

What is the passing score for CKS?

You need at least 67% to pass.

Is the CKS exam hands-on?

Yes, it's performance-based, requiring you to solve tasks in a command-line environment.

What Kubernetes version is CKS based on?

As of 2025, it's aligned with v1.33 or the latest minor version.

Can I use documentation during the exam?

Yes, you can access official Kubernetes documentation.

What is RBAC in Cluster Hardening?

RBAC stands for Role-Based Access Control, which limits user permissions to only what's necessary.

Why minimize base image footprint?

It reduces unnecessary software in containers, lowering vulnerability risks.

What are CIS benchmarks?

They are security configuration guidelines for Kubernetes components.

How to prepare for Supply Chain Security?

Practice image scanning and understanding SBOMs with tools like Trivy.

What is pod-to-pod encryption?

It's securing communication between pods using tools like Cilium or Istio.

Are there practice simulations for CKS?

Yes, the exam includes access to simulators with 20-25 questions.

How long is CKS certification valid?

It's valid for 2 years.

What tools for runtime security?

Tools like Falco for behavioral monitoring.

Is CKS suitable for beginners?

It's intermediate; beginners should start with Kubernetes basics and CKA.

What is etcd in Kubernetes?

Etcd is the key-value store for cluster data, needing secure config.

How to manage Kubernetes secrets?

Use built-in Secrets to store sensitive data encrypted.

What is kernel hardening?

Using tools like AppArmor to restrict process behaviors on the host.

Where to register for CKS?

Through the Linux Foundation Training portal.