Summary & Tips

If you are just starting to explore Kubernetes and the cloud native space, I recommend taking the KCNA certification first. Studying for this exam will help you build a strong foundation in Kubernetes. It is also multiple-choice, so even if you have little to no experience with Kubernetes, you can still do well on this exam. After that, take the KCSA, which focuses on security. Once you are comfortable with Kubernetes or have been working with it for a while, then you can take the CKAD, CKA, and CKS certifications.

Certification Tips

1. Read the Curriculum

   • https://github.com/cncf/curriculum

2. Read Important Tips

   • https://docs.linuxfoundation.org/tc-docs/certification/tips-cka-and-ckad

   • https://docs.linuxfoundation.org/tc-docs/certification/important-instructions-cks

3. Read the FAQs

   • https://docs.linuxfoundation.org/tc-docs/certification/faq-cka-ckad-cks

4. Read Allowed Resources

   • https://docs.linuxfoundation.org/tc-docs/certification/certification-resources-allowed#certified-kubernetes-administrator-cka-and-certified-kubernetes-application-developer-ckad

   • https://docs.linuxfoundation.org/tc-docs/certification/certification-resources-allowed#certified-kubernetes-security-specialist-cks

5. CKAD, CKA, and CKS are performance-based exams, each with a time limit of 2 hours to complete the tasks. Hence, you need to work quickly on each task. Below are the things you need to be familiar with to perform better on the actual exam:

   • Study kubectl and other basic shell commands

     • kubectl with k alias and Bash autocompletion

       • https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands

     • yq and jqfor YAML/JSON processing

     • tmux for terminal multiplexing

     • curl and wget for testing web services

     • man and man pages for further documentation

   • Creating alias and variables to shorten long commands

     • Fast dry-run output

     export do="--dry-run=client -o yaml"

     We can run kubectl run my-pod --image=nginx $do > my-pod.yaml . Short for "dry output" and the syntax > writes the output to file where we can further customize the configuration.

     • Fast resource deletion

     export now="--force --grace-period 0"

     We can run kubectl delete my-pod $now and don't have to wait for ~30 seconds termination time. This can save some time especially if a resource deletion took a little longer.

     • Setting alias for selecting namespace

     alias kn='kubectl config set-context --current --namespace '

     We can simply use kn default or kn custom-namespace to set the namespace we are working on.

   • Shortcuts for Vim

     • /<search-keyword> - search

       • Helpful in searching text in a file (e.g. searching replica set: /replicaSet )

     • :<number> - go to linenumber

       • Helpful in debugging syntax errors based on line number

     • G - go to the last line of the document

     • gg - go to the first line of the document

     • More reference here: https://vim.rtorr.com/

   • Understanding JSONPath

     • Example use cases:

       • Get container images used by all pods

         kubectl get pod -o jsonpath='{.items[*].spec.containers[].image}{"\\n"}'

       • Get pod names

         kubectl get pods -o=jsonpath='{.items[*].metadata.name}{"\\n"}'

     • Reference: https://kubernetes.io/docs/reference/kubectl/jsonpath/

   • Need to get information about the fields of a resource? Use kubectl explain to check resource definition.

     kubectl explain pod
     kubectl explain pod.spec.containers.securityContext

     • Alternatively, refer to this page: https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands

   • Sorting using kubectl

     kubectl get pods --sort-by=.metadata.name=desc
     kubectl get pods --sort-by=.metadata.creationTimestamp