Hands-on Lab·Certified Kubernetes Security Specialist
Common CKS Task Mistakes
On a performance exam nothing tells you that you were wrong. Every one of these five produced a success message on a real cluster and left the task unfinished, which is the only failure mode that matters when there is no answer sheet.
Working at Exam Speed Guide 39 of 40 Intermediate
- Kubernetesapiserver v1.36.4, kubelet v1.36.3
- Runtimecontainerd 2.2.6
- CNICilium 1.18.1 - tunnel/VXLAN, with Hubble relay and UI
- Host OSUbuntu 26.04 LTS, kernel 7.0.0-29
- Built withkubeadm v1.36.3 - podSubnet 10.244.0.0/16, serviceSubnet 10.96.0.0/12
- TimeAbout 15 min
- Reviewed25 August 2026
Written against the versions above. All five were run on a live cluster. The messages, the warnings and the refusals are the apiserver's own.
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| CKA6001 | 192.168.0.46 | Ubuntu 26.04 LTS | Control Plane Node (tainted NoSchedule) | 2 Core | 4 GB | 50 GB |
| CKA6001-NODE01 | 192.168.0.47 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
| CKA6001-NODE02 | 192.168.0.48 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
Before you start
- guide 18 - two of the five are about that admission controller.
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The label that warns and stops nothing
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Enforcing it afterwards, which is the other half of the same trap
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The dry run that agrees with you
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Two more, and both are one word