NOTICE: This information will be out of date in 9/2020 when the test is updated. Most of the information i put it here should be in-step with the new test but since the test isn’t out yet, I cant say for sure.
I decided a while ago that I wanted to go for the Certified Kubernetes Administrator certification. Little did I know the amount of work and struggles I’d deal with through the process, though I think that’s normal for most of us. We see a new solution set taking hold, and we play around with it, get some experience, then we decided to take it to the next level. It’s kinda like dating, but really, not like it at all. If you’re reading this because you’re thinking of going for the exam yourself, here are some things right off the bat.
Certified Kubernetes Admin Test Tips
The CKA is a practical exam. There is no multiple choice questions on this test. Its all you figuring out what’s broken, deciding how to fix it, and then fixing it. The end result is what counts more than how you perform a task. So if you have a broken cluster, as long as you get it fixed and back into a “ready” state, you’re good. The CKA can give partial credit. So even if you know half of the answer, do half of the question. This can be critical between a pass and fail.
The CKA is open book. You can use kubernetes.io/docs, and kubernetes github page. I’m not a fan of open book tests, because it means that the biggest factor against you is time. You’re given 3 hours to perform the 24 tasks on the exam, and since its open book. being stuck on one question will lead to a failure on others. For myself, I was searching everywhere for a CNI link that I lost track of time, and didn’t perform 3 other tasks. So there were 4 questions that didn’t even have answers. No bueno.
JsonPath will be crucial in the CKA. I had a lot of questions requiring you to pull data and spit it out in a different form. This was basically performed with custom-columns, or –sort-by functions within Kubernetes. Its good to be aware of how to use both. Though these questions aren’t normally weighed as heavily, they can be the difference between a pass and a fail. Almost every test has you use ETCDctl, and KubeADM, but be aware of these solutions, and how to utilize them in an administrator role. I myself was expecting some documentation to be available when using KubeADM to create a cluster, that was not. This was the biggest factor in failing my first test. When I had to install a CNI for the cluster to become “Ready” and the documentation didn’t have a CNI link to use, it became a really bad situation because of time.
The CKA is based in Linux. This should be no surprise to anyone, but I’ll state the obvious for those in the back. Learn to troubleshoot basic Linux issues. This means learning how to copy, checking service logs, and using an editor like VIM, VI, etc. These are all crucial as you can download the solution you may want, but again, that takes time, and can lead to a bad situation. I suggest learning how to navigate VI, as “Kubectl edit” opens a very similar environment to VI to edit a service/deployment/pod.
Commands to remember: simply typing “kubelet” will bring up the kubelet logs, I stumbled upon this while I took the exam, not sure if this is a product in the exam, but its good to know when troubleshooting node failures. “Journalctl -u kubelet” will continue to hold you up if kubelet doesn’t get the job done, and you can grep the error code. These were key for failed nodes/master nodes.
Alright, enough of my gabbing, about what I learned. What course work should you follow? Well here is my take on the course-work.
Absolute Beginner: Start with Nigel Poulton’s Pluralsight courses, then move from there to the Pluralsight CKA track. These give you great perspective to what K8s is and what they can do.
Test-Prep and Skill Development: This course literally made the lightbulb shine in my head about what what the CKA was about. I cannot recommend this course enough. I got it on sale, and only got it for 13$, so this does go on sale and can make your life WAY easier. This uses kodekloud as the lab tests and the tests are extremely good for prepping for the test. https://www.udemy.com/course/certified-kubernetes-administrator-with-practice-tests/
One thing to keep in mind is there are like 7 contexts during the test. Some questions require you to change your context, and some questions you will SSH directly into a specific node. If you need to change your context, there will be a reddish pink box in the upper left. Make sure to copy and paste that into the terminal before you do anything. This is critical, as you could do a question correctly in the wrong context and not get credit.
If you spend 5 minutes on a question and have not gained ground on your answer, move on. This is critical, as my first test resulted in a fail because I spent far too much time on a question instead of working on other questions. This means to jump past the questions you aren’t moving forward on, or the one you are spending too much time in kubernetes.io and check out the next one. The test will let you mark these questions to review later, so it will allow you to go back.
If you SSH into a node, and then run “sudo -i” in order to elevate rights, be wary how many times you exit. This can kick you out of the terminal completely. If that happens the proctor may tell you to “refresh the console”. Now, it may have been a glitch for me, but when I refreshed the console I lost all the flags I set on my unanswered questions. I remembered most of the numbers, but I figured it’s something to keep in mind.
These are all just my thoughts in what aided me to get a pass, and I hope aids you. In the end, I hope you become a helmsman and a happy CKA.