Why take the CKA as a Software Engineer?

I am currently working as a software engineer, so why should I bother with a DevOps-related certification, you may ask? One could say that the CKAD is enough for my job. And to be honest, this is not false, but it is also not quite true either. The reason why I decided to go for the CKA is to gain a better understanding of Kubernetes’ architecture, components, cluster lifecycle, and other aspects and tasks that are important for operating a production-grade cluster. Even if some cloud providers offer managed solutions and one-click cluster upgrades, I still believe that it’s important to understand the underlying and fundamental concepts of the technology you are working with. This holds true for almost any technology you use or rely on. It’s impossible to be an expert in all tech stacks, but a fundamental understanding and knowledge of the tools you use every day will always be beneficial.

The second reason is that I really like topics around modernization, cloud-native engineering, and especially architecture. During my preparation for the CKAD, I treated Kubernetes almost like a black box and only operated on the client and API level, but the CKA allowed me to learn more about the internal building blocks, design choices, and setup behind Kubernetes. For the first time, I learned how to troubleshoot cluster issues where I previously always needed external help.

My Preparation

I actually didn’t use a lot of resources to prepare for my CKA exam. Since I already had some Kubernetes knowledge and had passed the CKAD exam before, I had a foundation to build upon, which definitely helped.

CKA Course on Udemy (KodeKloud)

Like many others, I used the CKA course from KodeKloud on Udemy as a primary resource for covering the CKA syllabus. I already took the CKAD course from the same author back then, and I was very happy with it. If you already took the CKAD before, the CKA course will feel familiar. There are video lessons followed by hands-on labs that you can do directly in your browser, which I found very useful and engaging. Practicing is important since the CKA, just like the CKAD, is a hands-on exam where you solve tasks in a virtual environment.

I would recommend you wait for one of Udemy’s (flash) sales to buy the course. The value you get out of this course is absolutely worth it. However, at times, the content felt a bit out of date and not always aligned with the syllabus, which is why I definitely recommend combining the course with other (free) resources.

KillerCoda

After I finished the Udemy course, I started with KillerCoda exercises, which are short tasks you can solve for free in a sandbox environment directly from within your browser. All you need is an account on the KillerCoda platform. You can practice as many scenarios as you want, completely for free, so it’s definitely worth checking out. During my preparation, the scenarios by Kim Wüstkamp got put behind a paywall, though, which I didn’t pay for, so I can’t give any recommendation here. However, there are a lot of community scenarios available that I can definitely recommend, especially the ones made by Omkar Shelke. You might be surprised or even shocked by the number of scenarios available, but most of them were very useful for my exam preparation.

Kubernetes – The Hard Way

To better understand how to set up a highly available cluster from scratch, I used Kubernetes – The Hard Way. For the best learning effect, it avoids kubeadm completely, which means you set up all cluster components yourself (certificates, CNI, routing, etcd, apiserver, networking, …). I wouldn’t say it is absolutely mandatory to do this just to pass the exam, but I think it’s still a very valuable experience and helps you better understand Kubernetes architecture. I also learned some new Linux commands while going through the tutorial, so I think there is always something new to learn.

KillerShell

Let me summarize KillerShell in one word: Awesome! It is definitely worth doing. With the purchase of your CKA exam, you will get access to two exam simulator sessions with distinct questions (17 per session). I took the first session two weeks before my exam. After that, I revisited some topics and tried to close the gaps I identified. One week later, just before my real exam, I used the second simulator session. I scored quite high in both sessions, but I’d say that the questions match the difficulty you can expect on the real exam, though not all questions in the exam were as challenging as those in the simulator.

The Exam

The exam is online (remote) and proctored. You will have to scan your room and make sure you have no forbidden items on your desk or nearby. The check-in process was very smooth for me this time. I prepared my desk the evening before, so I saved myself some stress in the morning when I took my exam.

I think I got 16 questions, all of which covered pretty much the whole syllabus of the CKA. The CKA is challenging as it requires you to context-switch a lot between plenty of topics. You will jump between deployments, priority scheduling, storage classes, persistent volumes, ingresses, config maps, resource limits, Helm, CRDs, cluster issues, horizontal pod autoscalers, the new Gateway API, and more. When I finished the last question, I still had 40 minutes left, which I used for one question I skipped and flagged earlier, and one that I wasn’t so sure about. Finally, I went through all questions again, made sure I covered all requirements, and verified my solutions.

Overall, the exam was fair. I really think that the key to success is just a matter of preparation. There is nothing magical about the exam. The tasks are clearly worded, and the instructions and hints are actually useful. It’s just up to you to solve them. In my case, there was no need for super fancy and complex Linux commands or anything spectacular. It was very grounded, but covered a variety of topics, which is where things get challenging, especially under time pressure. Practicing KodeKloud mock exams, KillerCoda, and KillerShell definitely helped here.

I got the results 24 hours after I took the exam. You can view them on the Linux Foundation Training Portal. In my case, I scored 95%.

My Tips

Here are some of my personal tips based on my exam experience.

Don’t bother defining custom aliases: you will jump from node to node (via SSH), and all aliases will be lost as you jump to another node. Additionally, all the aliases you will need (for example, k for kubectl) are already set up. When I reached my last question, I still had ample time left. Defining aliases will not determine whether you pass or not.

Try to get a good grasp of all topics: The CKA covers more topics than the CKAD, so it’s better to get a good understanding of many topics rather than becoming an “expert” in only a few. You can always look up some specifics in the docs or by using kubectl explain.

Get familiar with kubectl explain: The CKA deals with a lot of resource types. Sometimes, it just feels impossible to remember all specification fields and such. The good thing is that it’s not even necessary. You can still consult the Kubernetes docs to look for keywords, explanations, etc. Looking up one particular field may sometimes be faster with kubectl explain, so it’s better to get used to it. I used it at least two times during my exam.

If you get stuck, move on to the next question: Sometimes, a question doesn’t make much sense to you, or you don’t grasp it right away. This happened to me once during the CKA. I flagged the question and returned to it later. On my second attempt, I solved the issue.

Keep an eye on the syllabus: Sometimes, exam topics can change, and course content may not be up to date. Always check out the official exam syllabus and verify that you covered all aspects of the exam as part of your preparation. Recently, ETCD-related maintenance tasks were removed from the syllabus, which is not yet reflected in all courses. Being aware of the most recent syllabus ensures that you set the right priorities.

Conclusion

There we go! My CKA experience was very positive, and I learned a lot of new topics. All you need to pass this certification is dedication, one Udemy course, and practice via KillerCoda and KillerShell.

I hope this article was useful to you. If you are preparing for your CKA certification, just keep going, you’ve got this! I wish you the best of luck on your journey

Why CKAD?

Containerization and container orchestration technologies like Kubernetes become more popular every day. In fact, I work with these technologies almost every day in my current job as a Software Engineer. My employer gave me the chance to upskill in this area and prepare for the CKAD exam, which was a great opportunity to sharpen my Kubernetes and cloud-native skills.

My motivation for the CKAD was mainly driven by closing knowledge and skill gaps, improving overall understanding of Kubernetes and cloud-native strategies, profiting from high quality training, being able to better communicate with other technical stakeholders (e.g., DevOps), as well as sharing my knowledge with my team.

Preparation Resources

As part of my exam preparation, I used several resources and materials from various sources. I will present each of them here briefly, including aspects I liked and didn’t like about them.

CKAD Udemy Course by Mumshad Mannambeth

Like many other CKAD candidates, I used the popular Udemy course “Kubernetes Certified Application Developer (CKAD) with Tests” by Mumshad Mannambeth and KodeCloud as my main exam preparation. The course is overall really well-made, well-structured, comes with plenty of small exercises (in the KodeCloud environment), and teaches you everything you need to know to go into the exam.

The course is very worth its money (especially on Udemy’s flash sales), and I highly recommend taking it. I would, however, not solely rely on one resource, which is why I combined this course with other training materials.

CKAD Certification Path by Pluralsight

In addition, I watched the whole CKAD preparation course on Pluralsight, which was about 15 hours of video content. Pluralsight requires a subscription to access its materials on the platform. Luckily, I already had such a license thanks to my employer. The video course and study materials are of very high quality, and I can really recommend watching it, if you have the chance, of course. I wouldn’t say that you need to combine it if you already have the Udemy course, but it’s a very good addition and reflects the exam topics from a slightly different angle.

Some people learn better when they watch someone guiding and explaining topics. Pluralsight is great for that! There are also some hands-on exercises, which, however, were not extensive and often just a repetition of what the instructor has already done.

Official CKAD Training by the Linux Foundation

This was the only resource I was disappointed by. The course didn’t feel as well-made as the Udemy course, for example. It contained spelling mistakes, code snippets were sometimes badly formatted, the audio quality was not always great, and some textual explanations required knowledge that candidates may not already have. On a positive note, this was the only course where you had to set up your own two-node cluster using the kubeadm tool, which helped in understanding the overall architecture of Kubernetes. The course went a lot deeper in some aspects (especially hands-on labs), but still didn’t convince me overall, especially knowing how much this training normally costs.

KillerCoda

KillerCoda is a free-to-use platform that offers a Kubernetes playground. It is a sandbox environment for you to play around and experiment, but it also comes with a lot of scenario-based exercises that you can solve at your own pace. These exercises are usually very small and can be solved within a few minutes or less.

I did all CKAD exercises on KillerCoda. I especially used the platform a lot when I didn’t have a lot of time but still wanted to learn a bit. Checking off one or two more scenarios can give you exactly the satisfaction you’re looking for, especially when you are running low on time or your everyday work is demanding a lot from you.

CKAD Exercises on GitHub

There are plenty of small exercises available for free on platforms like GitHub shared by the community. One example is this repo by dgkanatsios, which I used myself and found very helpful. These are especially helpful when you want to increase your speed when typing or train your memory for common imperative commands.

KillerShell

If you book the exam via the Linux Foundation, you will get access to an excellent exam simulator called KillerShell. While I think all the other study resources I’ve described so far are great to learn new topics and close your gaps, KillerShell will undoubtedly prepare you the most for the actual CKAD exam. The exam simulator is so well-made that I felt very confident when I saw the real exam environment for the first time.

KillerShell comes with two sessions, each valid for 36 hours. You will have the same questions in both sessions. However, you can redo the exam as many times as you like, which is something I highly recommend you do. Even though I passed on my very first attempt, there were still some things I got wrong. Appreciating my strengths and focusing on my weaknesses allowed me to score even higher in the subsequent attempts. I’d say that KillerShell “over-prepares” you for the exam, as the questions are more difficult. This means that if you handle KillerShell with ease, you will be fine in the real exam. In summary, it is very much worth it!

Exam Experience

Now, I won’t repeat how to enroll, schedule, and register for the exam, since the documentation on the Linux Foundation covers all of that in extensive detail.

One day before the exam, I cleaned up my office, removed anything not needed or allowed from my desk, so that in the end, I only had one monitor, my keyboard, mouse, and a microphone on my desk. I scheduled my exam for 9 AM, as I perform better in the morning.

I started the check-in process on time and walked my way through the instructions and the room scanning. Additionally, I had to move my camera around to show my surroundings. This is normal and expected, and shouldn’t bother you any further; the rotor is just doing his/her job.

After the check-in was done, I saw the exam. One click on “Start” started the exam. I started directly with the first question without further ado. I connected to the node via ssh, solved the problem, exited out of the node, and moved on to the next question. I basically did this until the very last question. With the extra time in the end, I revisited my answers and verified that I hadn’t forgotten or missed something.

At the end, you submit your exam, and that’s it. You won’t know if you passed or not. You will get the results 24 hours later, so you will need to be a bit patient. But given you prepared well enough, there shouldn’t be a bad surprise 🙂

General Tips I’d Give a Friend

Here are a few tips based on my experience when you want to take the exam. This is very subjective, and it’s totally fine if you disagree with some of them.

Don’t bother defining custom aliases: you will jump from node to node (via ssh), and all aliases will be lost as you jump to another node. Additionally, all aliases that you will need (k for kubectl) are already set up. When I was done with the exam, I still had ca. 45 minutes left, so if you prepare well, you won’t need aliases to be faster.

Upload and validate your identification proof before the exam date: The check-in process at the beginning of the exam can be stressful for some, as you will be proctored the whole time, and you will have to scan your environment. You can already offload one step, which is your ID proof. You can already upload your ID card (or similar) upfront and have it validated before sitting the exam.

Don’t get hung up on questions: If you feel stuck, mark the question for review, and come back to it later. When switching to another question, don’t forget to exit out of your current node and connect to the one from the next question. In my opinion, this should only happen once or twice; otherwise, something went wrong in the preparation.

Train with the keyboard layout you want to use during the exam: If you have multiple keyboards (e.g., a US, a French, and a German one), I recommend doing the exercises with the keyboard you want to use during the exam. It will be easier to build muscle memory this way.

Be disciplined during your preparation: I personally think that’s important to keep studying while you prepare for the exam and avoid larger gaps. It’s fine to take a break from time to time, but you shouldn’t reach a point where you start forgetting things you learned when you started.

Enjoy the journey: If you took your time and prepared well for the exam (e.g., using the resources outlined above), you will actually enjoy the exam a lot. The exam was very fair. The questions were clearly worded, and the objective was always clear. It’s then just up to you and your skills to solve the problem. This gives you freedom and doesn’t feel at all like a multiple-choice question type of exam.

Keep an eye on the syllabus: Sometimes, exam topics can change, and course content may not be up to date. Always check out the official exam syllabus and verify that you covered all aspects of the exam as part of your preparation. In my case, there was no section on Kustomize in any of the resources I used for my preparation, even though it was part of the official syllabus. Better safe than sorry!

Conclusion

There we go! This was my exam preparation! I hoped it was useful to you! If you want to reach out and ask specific questions, feel free to contact me on social media.