CKS — What is CKS?
What is the CKS Certification?
The Certified Kubernetes Security Specialist (CKS) is the most advanced certification in the CNCF Kubernetes program. It validates your ability to secure container-based applications and Kubernetes platforms during build, deployment, and runtime.
CKS sits at the top of the Kubernetes certification hierarchy. It is offered by the Cloud Native Computing Foundation (CNCF) in collaboration with The Linux Foundation.
CKS is not an entry-level exam. It assumes you are already a competent Kubernetes administrator. You must hold a valid CKA certification before you can even register.
Performance-Based Exam Format
Like CKA, the CKS is a hands-on, performance-based exam. There are no multiple-choice questions. You work directly in a terminal connected to live Kubernetes clusters.
What makes CKS different from CKA:
- Security-focused tasks — You configure audit policies, write Falco rules, create AppArmor profiles, scan images, and enforce admission policies
- Multiple security tools — The exam environment includes Trivy, Falco, kube-bench, AppArmor utilities, and more
- Higher complexity — Tasks require understanding how multiple security layers interact (e.g., NetworkPolicy + PodSecurity + RBAC together)
- Stricter passing score — CKS requires 67% vs CKA’s 66%
During the exam, you will:
- Harden API server configurations
- Create and apply NetworkPolicies to isolate workloads
- Configure Pod Security Admission for namespaces
- Write Seccomp and AppArmor profiles
- Scan container images for known vulnerabilities
- Detect runtime anomalies using Falco
- Enable and configure audit logging
- Encrypt Secrets at rest in etcd
- Fix misconfigurations identified by CIS benchmarks
CKA Prerequisite Requirement
| Requirement | Details |
|---|---|
| Must hold valid CKA | Your CKA must be active (not expired) at the time of CKS registration |
| CKA validity | CKA is valid for 2 years from the date of passing |
| No exceptions | You cannot take CKS without CKA — the system blocks registration |
| CKAD is not sufficient | Only CKA satisfies the prerequisite, not CKAD |
Pro tip: If your CKA is about to expire, renew it before registering for CKS. If CKA lapses after you register but before you take CKS, check The Linux Foundation’s current policy — requirements may have been enforced at registration time.
Who Should Take CKS?
| Role | Why CKS? |
|---|---|
| Security Engineer | Validate K8s-specific security skills — runtime protection, image scanning, policy enforcement |
| DevSecOps Engineer | Shift-left security into CI/CD pipelines — image scanning, admission control, supply chain hardening |
| Platform Engineer | Build secure multi-tenant platforms — Pod Security Standards, NetworkPolicies, RBAC hardening |
| Site Reliability Engineer (SRE) | Detect and respond to runtime threats — Falco rules, audit logging, anomaly detection |
| Cloud Security Architect | Design defense-in-depth for K8s — CIS benchmarks, encryption at rest, mTLS |
| Compliance Engineer | Enforce organizational security policies — OPA/Gatekeeper, CIS benchmark scanning |
| CKA Holders | The natural next step — deepen your Kubernetes expertise into security |
Career Benefits
CKS certification provides measurable career advantages in the security-focused Kubernetes market:
Salary Premium
CKS holders command a 15–25% salary premium over CKA-only holders in security-adjacent roles. As organizations move workloads to Kubernetes, the demand for professionals who can secure these environments far outpaces supply.
Job Market Demand
Security is consistently the #1 concern for organizations adopting Kubernetes (per CNCF annual surveys). Roles that specifically mention CKS or Kubernetes security have grown significantly:
- DevSecOps Engineer — Increasingly requires CKS or equivalent
- Cloud Security Engineer — K8s security is now a core requirement
- Platform Security Lead — CKS validates the hands-on skills needed
Differentiation
Most Kubernetes professionals stop at CKA or CKAD. Holding CKS immediately differentiates you:
| Certification | Approximate Holders Worldwide |
|---|---|
| CKAD | ~30,000+ |
| CKA | ~40,000+ |
| CKS | ~8,000+ |
The CKS holder pool is significantly smaller, making it a stronger differentiator on your resume.
Vendor-Neutral Credential
CKS skills apply across all Kubernetes platforms:
- AWS EKS — Security groups, IRSA, Pod Identity, GuardDuty for EKS
- Azure AKS — Azure Policy, Defender for Containers, Workload Identity
- GCP GKE — Binary Authorization, Workload Identity, Security Posture
- On-premises — kubeadm, Rancher, OpenShift — the security fundamentals are identical
Certification Landscape
The CNCF offers three Kubernetes certifications arranged in a clear hierarchy:
┌─────────────────────────────────────────────┐
│ CKS (Advanced) │
│ Certified Kubernetes Security │
│ Specialist │
│ Requires: Valid CKA │
├─────────────────────────────────────────────┤
│ CKA (Intermediate) │ CKAD (Inter.) │
│ Certified Kubernetes │ Certified K8s │
│ Administrator │ App Developer │
│ Requires: None │ Requires: None │
└─────────────────────────────────────────────┘
| Certification | Focus | Level | Prerequisite |
|---|---|---|---|
| CKAD | Application development & deployment on Kubernetes | Intermediate | None |
| CKA | Cluster administration, installation, troubleshooting | Intermediate | None |
| CKS | Cluster & workload security, runtime protection | Advanced | Valid CKA |
CKS is the capstone. It assumes everything you learned in CKA and layers security expertise on top. The recommended path is CKA → CKS. If you’re a developer, consider CKAD → CKA → CKS.
What CKS Covers (High-Level)
The CKS exam tests six security domains:
| Domain | Weight | Key Topics |
|---|---|---|
| Cluster Setup | 10% | NetworkPolicies, CIS benchmarks, Ingress TLS, node metadata protection |
| Cluster Hardening | 15% | RBAC lockdown, ServiceAccount hardening, API server audit, upgrade strategy |
| System Hardening | 15% | AppArmor, Seccomp, OS-level hardening, reducing attack surface |
| Minimize Microservice Vulnerabilities | 20% | Pod Security Standards, OPA/Gatekeeper, Secrets management, runtime sandboxes |
| Supply Chain Security | 20% | Image scanning, allowlisting registries, signing, image policies, static analysis |
| Monitoring, Logging & Runtime Security | 20% | Falco, audit logging, immutable containers, behavioral analysis |
The three 20% domains make up 60% of the exam. Prioritize Microservice Vulnerabilities, Supply Chain Security, and Runtime Security in your study plan.
Practice Questions
Q1: What is the prerequisite for taking the CKS exam?
Show Answer
You must hold a valid (non-expired) CKA certification. CKAD alone is not sufficient. Your CKA must be active at the time of CKS registration.
Q2: How does the CKS exam format differ from a traditional certification exam?
Show Answer
CKS is performance-based, not multiple-choice. You solve real security tasks on live Kubernetes clusters using a terminal. Tasks include writing Falco rules, creating AppArmor profiles, configuring NetworkPolicies, scanning images, and hardening cluster configurations — all hands-on.
Q3: Name three roles that benefit most from CKS certification.
Show Answer
- Security Engineer — Validates Kubernetes-specific security skills
- DevSecOps Engineer — Proves ability to integrate security into CI/CD and K8s workflows
- Platform Engineer — Demonstrates expertise in building secure multi-tenant Kubernetes platforms
Other strong candidates: SRE, Cloud Security Architect, Compliance Engineer.
Q4: Where does CKS sit in the CNCF certification hierarchy?
Show Answer
CKS is at the top of the hierarchy — it is the only advanced-level CNCF Kubernetes certification. It sits above both CKA and CKAD, and requires CKA as a prerequisite. The hierarchy is:
- Intermediate: CKA (administration), CKAD (development)
- Advanced: CKS (security)
Q5: What percentage of the CKS exam is covered by the three 20%-weight domains combined?
Show Answer
60%. The three domains at 20% each are:
- Minimize Microservice Vulnerabilities (20%)
- Supply Chain Security (20%)
- Monitoring, Logging & Runtime Security (20%)
Together, these three domains cover more than half the exam. They should be your highest-priority study areas.
Next: Understand the full exam structure with Exam Overview →
