The CKAD is a certification designed to test a candidate’s ability to manage objects within a kubernetes cluster. It is part of the suite of Kubernetes certifications offered by the Linux Foundation, which are CKAD, CKA, and CKS. Unlike the CKA, the CKAD is not a prerequisite for taking the CKS, which many consider to be the pinnacle of the Kubernetes certifications.
If you are more interested in taking the CKA after the CKAD, be sure to checkout my guide on passing the CKA here.
With that being said, let’s jump into what you need to know for passing the CKAD.
Topics on the CKAD
Unlike the CKA, the CKAD does not deal with kubernetes cluster administrative tasks such as kubeadm, etcd, or kubelet. It is purely on how to create and manipulate kubernetes objects. Because of that, make sure you are familiar with concepts such as:
- Pod Spec
- Workloads (CronJob, Deployment, Daemonsets)
- Secrets and ConfigMaps
- Network Policies
- PersistentVolumes, PersistentVolumeClaims, StorageClasses
- Roles/Rolebinding, Clusterrole and Clusterrolebindings
- Services and Ingresses
Since you will be working on your own browser, I would highly suggest that you keep a list of bookmarks for the exam which contains a list of documentations you can refer to.
Preparation Material
Prior to completing the CKAD, I spent a good amount of time preparing for the CKA thinking it would be a harder exam. However, I actually found the CKAD exam to be more difficult than the CKA exam. I’m not going to bore you with a list of resources, instead I’ll share with you the 2 core resources I’ve used to prepare for this exam:
killer.sh: A CKA/CKAD/CKS exam simulator that offers the closest experience to the real exam. (You can use walidshaari for a 20% discount, last tried April 14th 2021)
CKAD Practices: A github repo that contains a set of scenarios for various kubernetes objects creation and manipulations.
If you are interested in the resources I’ve used for the CKA exam, which are the same resources I’ve used for the CKAD exam, you can find them here.
Example Questions
- How do you import a configMap object into your Kubernetes pod as an environment variable?
env:
- name: SPECIAL_LEVEL_KEY #Name of the Environment Variable
valueFrom:
configMapKeyRef: #Name of the ConfigMap Object
name: special-config
key: special.howhttps://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/
2. What is the syntax for creating a CronJob that executes once every minute? What about once every hour?
spec:
schedule: "*/1 * * * *" #Every minutespec:
schedule: "0 * * * *" #Every hour at the beginning of the hourhttps://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/
3. How does a Network Policy select which pods its rules apply to? Can the pods be in a different namespace?
podSelector:
matchLabels:
role: db #The label on the podThe Networkpolicy is a namespaced object (kubectl api-resources --namespaced), therefore pods must exist in the same namespace as the network policy
https://kubernetes.io/docs/concepts/services-networking/network-policies/
Closing thoughts
The CKAD in my opinion is a harder exam to pass than the CKA exam but the CKA exam covers more in scope than the CKAD. If your end goal is to pass the CKA I would suggest that you go through the CKA exam first before the CKAD as your CKA training would prepare you for both exams.
As always, best of luck on your certification journey!
