Before taking the exam, I already had extensive experience using K8s, however always through managed services. I had to learn everything about how a K8s cluster is actually run.
I used the course hosted over A Cloud Guru. It is up-to-date, and covers everything needed for the CKA. The course is very hands-on, so if you sign up for it, I recommend doing the laboratories (they provide the environment) because the exam is a long series of tasks similar to what you would be asked to do during the lab sections of this course.
Furthermore, you should learn how to navigate the K8s doc. You can use it during the exam, so there is no point in learning every single field of every single resource. Do you need to create a pod? Go to the documentation for it, copy the basis example, and customize it.
When you register for the CKA certification exam on the Linux Foundation site, you will receive access to a simulated exam hosted by killer.sh. The simulation is significantly more difficult and longer than the actual exam: I attempted a simulation two days before the exam, and I achieved 55%. On the actual exam, 91%.
I highly recommend taking the simulation, not only to see how prepared you are, but to familiarize yourself with the exam environment.
The exam is 2 hours long, with a variable number of tasks. Points are also assigned based on how many tasks of a question you answered. You need a score of 66% to clear the exam.
During the exam you can access K8s documentation, use this power to your advantage. The environment in which the exam will run is based on XFCE. You will have a browser, a note pad, and a terminal you can use.
Being familiar with
vi can help you work more quickly, especially if you spend a lot of time in there, and you just use the browser to read the documentation.
You can use the note pad to keep track of which questions you skipped, or you want to revise later.
During your exam, you will work on multiple K8s clusters. Each question is about one cluster, and at the beginning of the question, it says which context you should use. Don’t jump to answering the question without having switched context!
To attend the exam, you will have to download a dedicated browser, called PSI Safe Browser. You cannot download this in advance, it will be unlocked for you only 30 minutes before the beginning of the exam.
Theoretically, it is compatible with Windows, macOS, and Linux: however, many users have problems with Linux. Be aware that there could be issues, and have a macOS or Windows machine available, if possible, as a backup plan.
This browser will make sure that you are not running any background application, and that you don’t have multiple displays (only one monitor, sorry!).
After you installed the browser, you will have to identify yourself with some official document. You will have to show that you are alone in the room, that your desk is clean, that there is nothing under your desk, and so on. You will have to show your smartphone, and then show that you placed it in some unreachable place. The whole check-in procedure takes time, and it is error-prone (I had to show the whole room twice, then the browser crashed, and I had to start from scratch again).
The onboarding procedure is the most stressful part of the exam: read all the requirements on the Linux Foundation Website, try to clear your desk from any unrelated things, and start the procedure as soon as possible. In my case, it took almost 50 minutes.
Their browser is not a perfect piece of software: in my case, the virtual environment inside this browser had a resolution of 800x600, making it impossible to have two windows on a side-by-side. However, you spend the huge majority of your time in the terminal, and sometimes on the browser to copy-paste snippets from the browser.
Keep a Windows or macOS machine nearby, if Linux doesn’t work for you;
Answering a question partially is better than not answering at all;
Always double-check the K8s context! The first thing you must do for each question, it is switching the context of your kubectl according to the instructions;
Create files for each resource you create, so you can go back and adjust stuff. Moreover, if you have time at the end of the exam, makes way easier to check what you have done;
Remember to have a valid ID document with you for the exam check-in;
Time constraints and the unfamiliar environment will be your greatest challenges: however, if you have used K8s in production before, you should be able to clear the exam without any major difficulty. Spending sometime training before is strongly suggested, no matter your level of expertise, just to understand the format of the exam.
Good luck, and reach out if you have any question, here in the comments or by email at firstname.lastname@example.org.