Online resources that will help you prepare for taking the Kubernetes Certified Administrator Certification exam.
Disclaimer: This is not likely a comprehensive list as the exam will be a moving target with the fast pace of k8s development - please make a pull request if there something wrong, should be added, or updated.
I tried to restrict the cross references of resources to kubernetes.io. Youtube videos and other blog resources are optional; however, I still found them useful in my k8s learning journey.
Ensure you have the right version of Kubernetes documentation selected (e.g. v1.26 as of January 2023 exam) especially for API objects and annotations.
LDR: practice practice practice
These are the exam objectives you review and understand in order to pass the test.
implment etcd backup and restore
Kubecon Europe 2020: Kubeadm deep dive
```
#etcd backup and restore brief
export ETCDCTL_API=3 # needed to specify etcd api versions, not sure if it is needed anylonger with k8s 1.19+
etcdctl snapshot save -h #find save options
etcdctl snapshot restore -h #find restore options
## possible example of save, options will change depending on cluster context, as TLS is used need to give ca,crt, and key paths
etcdctl snapshot save /backup/snapshot.db --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key -- cacert=/etc/kubernetes/pki/etcd/ca.crt
# evicting pods/nodes and bringing back node back to cluster
kubectl drain
Know how to configure applications with persistent storage
``` #### Storage Class example # #### Persistent Volume Claim example # kind: PersistentVolumeClaim apiVersion: v1 metadata: name: local-pvc spec: accessModes: - ReadWriteOnce storageClassName: local-storage-sc resources: requests: storage: 100Mi ## Persistent Volume example # apiVersion: v1 kind: PersistentVolume metadata: name: local-pv spec: accessModes: - ReadWriteOnce capacity: storage: 200Mi local: path: /data/pv/disk021 persistentVolumeReclaimPolicy: Retain storageClassName: local-storage-sc volumeMode: Filesystem ### Pod using the pvc # apiVersion: v1 kind: Pod metadata: name: nginx labels: name: nginx spec: containers: - name: nginx image: nginx volumeMounts: - name: local-persistent-storage mountPath: /var/www/html volumes: - name: local-persistent-storage persistentVolumeClaim: claimName: local-pvc ```
practice practice practice
Get familiar with:
Familiarize yourself with the documentation, initially concepts and mostly tasks, kubectl explain command, kubectl cheatsheet, and kubectl commands reference
kubectl api-versions
and kubectl api-resources
wih grep
for a specific resoruce e.g. pv, pvc, deployment, storageclass, ..etc can help figure out the apiVersion, and kind combined with explain below will help in constructing the yaml manifest
kubectl explain --recursive to construct out any yaml manifest you need and find its specd and details
When using kubectl for investigations and troubleshooting utilize the wide output it gives your more details
$kubectl get pods -o wide --show-labels --all-namespaces
or
$kubectl get pods -o wide --show-labels -A # -A is quicker than --all-namespaces
In kubectl
utilize --all-namespaces or better -A
to ensure deployments, pods, objects are on the right name space, and right desired state
for events and troubleshooting utilize kubectl describe if its pod/resource related and logs if it is application issue related
$kubectl describe pods <PODID> # for pod, deployment, other k8s resource issues/events
$kubectl logs <PODID> # for container/application issues like crash loops
* [fast with kubectl](https://medium.com/faun/be-fast-with-kubectl-1-18-ckad-cka-31be00acc443) e.g. the '-o yaml' in conjuction with `--dry-run=client` allows you to create a manifest template from an imperative spec, combined with `--edit` it allows you to modify the object before creation
kubectl create service clusterip my-svc -o yaml --dry-run=client > /tmp/srv.yaml kubectl create --edit -f /tmp/srv.yaml
* use kubectl [aliases](https://github.com/ahmetb/kubectl-aliases) to speed up and reduce typo errors, practice these alaises early at your work and study for the exam. some example aliases:
alias k='kubectl' alias kg='kubectl get' alias kgpo='kubectl get pod' alias kcpyd='kubectl create pod -o yaml --dry-run=client' alias ksysgpo='kubectl --namespace=kube-system get pod'
alias kd='kubectl delete' alias kdf='kubectl delete -f'
alias krmgf='kubectl delete --grace-period 0 --force' alias kgsvcoyaml='kubectl get service -o=yaml' alias kgsvcwn='watch kubectl get service --namespace' alias kgsvcslwn='watch kubectl get service --show-labels --namespace'
krmgf nginx-8jk71 # kill pod nginx-8jk71 using grace period 0 and force
* Enable [kubectl autocomplete](https://kubernetes.io/docs/reference/kubectl/cheatsheet/#bash). Autocomplete is the life saviour in any timebound exam as well as our day to day work (e.g. If autocomplete enabled `k -n [Press Tab]` will suggest available namespaces). Example command to enable autocomplete is available at official [kubectl Cheat Sheet](https://kubernetes.io/docs/reference/kubectl/cheatsheet/#bash) page, you don't have to remember anything.
source <(kubectl completion bash) # setup autocomplete in bash into the current shell, bash-completion package should be installed first. echo "source <(kubectl completion bash)" >> ~/.bashrc # add autocomplete permanently to your bash shell.
alias k=kubectl complete -F __start_kubectl k
## Miscellaneous (resources not allowed during exam):
1. [Troubleshooting use cases by Ian/Container solutions](https://github.com/ContainerSolutions/kubernetes-examples)
## Popular training and practice sites:
*Double check if the course is uptodate with the latest exam information (e.g. api, or curicuilim)*
- [Mumshad CKA with practice tests and mock exams](https://www.udemy.com/course/certified-kubernetes-administrator-with-practice-tests/) - Highly recommended
- [Killer.sh CKA simulator](https://killer.sh/cka) ⟹ use code **walidshaari** for **20%** discount - they update frequently
- [AWS Container hero NANA CKA course](https://www.techworld-with-nana.com/kubernetes-administrator-cka)
- [Kube Academy free How to prepare for the CKA exam training](https://kube.academy/courses/how-to-prepare-for-the-cka-exam)
- [A Cloud Guru - Certified Kubernetes Administrator (CKA)](https://acloud.guru/overview/certified-kubernetes-administrator)
- [Pluralsight CKA course](https://www.pluralsight.com/paths/certified-kubernetes-administrator) by [Anthony E. Nocentino
](https://twitter.com/nocentino)
- [LinuxAcademy/ACloudGuru CKA course](https://acloud.guru/learn/7f5137aa-2d26-4b19-8d8c-025b22667e76)
- [rx-m online CKA course](https://rx-m.com/cka-online-training/)
- Duffie Cooly [hands-on CKA video](https://k8s.work/cka-lab.mp4) using KinD and accompanying [notes](https://hackmd.io/@mauilion/cka-lab)
- [Stilian Stoilov](https://www.linkedin.com/in/stilian-stoilov-379972a9/) [practice questions](https://github.com/StenlyTU/K8s-training-official) - 50+ tasks with increasing difficulty.
- [Killercoda in-browser CKA Playground and Challenges](https://killercoda.com/killer-shell-cka) - FREE
# Quick review material
- Adnan Rashisd CKA notes: can be found at https://adnan.study/
# What's Next:
- Learn more about Kubernetes core components from [Duffie Cooly](https://twitter.com/mauilion) [TGIK Grokking playlist](https://www.youtube.com/playlist?list=PL7bmigfV0EqS6WxgWlH-p4dhkfuwcZ6-E)
- [CKAD Certified Kubernetes Application Developer](https://www.cncf.io/certification/ckad/)
- [CKS Certified Kubernetes Security Specialist](https://github.com/walidshaari/Certified-Kubernetes-Secuirty-Specialist)
- Klustered: live youtube series of advanced level of internals troubleshooting. fun and interesting to watch [Klustered](https://www.youtube.com/playlist?list=PLz0t90fOInA5IyhoT96WhycPV8Km-WICj)