How I got CKAD Certification (2021) in 3 Weeks

CKAD Certified Kubernetes Application Developer by LinuxFoundation


Today I am celebrating my 31st certification, after having passed the CKAD: Certified Kubernetes Application Developer certification issued by The Linux Foundation.

General information about the certification

The purpose of certification

The Certified Kubernetes Application Developer (CKAD) certification is designed to ensure that certification holders have the skills, knowledge and competencies necessary to assume the responsibilities of Kubernetes application developers. A Kubernetes certified application developer can define application resources and use basic primitives to build, monitor and troubleshoot scalable applications and tools in Kubernetes.

The difference between CKAD, CKA, CKS

  • CKAD (Certified Kubernetes Application Developer): CKAD is intended for developers who will use Kubernetes as an orchestrator in their development projects and cloud engineers.
  • CKA (Certified Kubernetes Administrator): CKA is intended for DeVops, Engineers and Cloud Architects and Architects. CKA certification is much more difficult than CKAD.
  • CKS (Certified Kubernetes Security Specialist): CKS is intended for security experts, DevOps experts, Cloud Architects, Security Architects. CKS is a very difficult certification, and it takes a lot of time to be prepared.

The content of the certification:

  • Core Concepts (13%)
  • Configuration (18 %)
  • Multi-Container Pods (10%)
  • Observability (18%)
  • Pod Design (20%)
  • Services & Networking (13%)
  • State Persistence (8%)

Difficulties of the exam

  • The time: 2 hours are very short to do all the labs. In general, certifications where documents are allowed tend to be more difficult than MCQ certification.
  • YAML files: Files are long, a small training error on a line can take time to fix it (luckily there is a solution for that).

Practical exercises to pass necessarily before the exam

Means of preparation that I advise

My first tips for successful certification on the first attempt and with a 100% score

During the exam:

  • I strongly recommend answering questions based on their weight. All questions have their weight displayed. Some issues with a lower weight will take longer. So it is better to go back to these questions once you have finished the higher weight issues.
  • Use the exam notepad.
  • You should know that you only have the right to open one tab of the maximum browser! Therefore, it is not possible to open several links at once.
source <(kubectl completion bash)
alias k=kubectl
complete -F __start_kubectl k
  • a] Imperative — Manage K8s object using CLI ( imperative commands)
  • b] Declarative — By defining K8s objects in yaml file.
:set nu # afficher les numéros de lignes
:set nu! # désactiver l'affichage des numéros de lignes

How many days did the preparation take me?

Response: 2 weeks and 4 days (2 hours per day).
The duration of preparation is very personal and depends above all on the experience of each one with Kubernetes.

  • I had previous experience with Rancher v1.6 and Rancher v2.1.
  • I used Docker swarm when it was unstable.
  • I had a basic experience with Openshift 3.1.
  • I also used Spinnaker 1.19 and it was a hell of an experience as I lost 3 weeks in the encryption due to its instability and lack of documentation.
  • I was good at Docker

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