Kubernetes - Learning Guide for certifications

Certainly, Linux containers have become the de-facto capsule in which software is being delivered. Years ago we used to grab tomatoes with our own hands in the supermarket, but logistics get easier if fruit is put on trays. Fortunately, docker images as recipients do not pollute the oceans :)

Many disciplines are leveraging this model for many already known reasons (Big data, Microservice applications, ML model delivery, telco NFV...), so at some point understanding core concepts becomes a must.

Although I had certain conceptual knowledge, I decided taking the challenge of knowing nuts&bolts details of the most prevalent tool for throwing and running containers in several boxes, a term so called orchestration in which since 3 years ago, Kubernetes is the way to go, since it has become the equivalent in tech of ibuprofen in the domain of home remedies, as I said before, due to the fact that independent disciplines are adopting it as its underlying virtual infra provider.

Putting a goal is always good, so the 2 Kubernetes certifications of the Linux Foundation are excellent milestones.

• CKA is oriented for having a cluster up and running ready for applications to run on top. IMHO, the most challenging exam, after which you understand clearly why leveraging a PaaS service like Azure Kubernetes Service is great
• CKAD is more application oriented. It requires mastering core kubernetes objects on top of which application legos are built.

My purpose was mastering Kubernetes, so I accidentally studied the content of both exams at the same time. Looking back I recommend this approach

In short, what worked for me.

• Kubernetes the hard way. Canonical Kubernetes exercise by the discipline guru, Kelsy Hightower in which you have to grab naked Linux servers and step by step, you deploy your own cluster. It took me 2 full days, but the experience is very enabling for learning core concepts, although you should end up understanding why this is not the way to go in production due to the inner complexity of this artisan approach. In an exam oriented model, if your goal is the CKA, a must do, period. For the CKAD, interesting to have. My repo here as a reference on how to do it using Azure IaaS tricks https://github.com/SeryioGonzalez/kubernetes-the-hard-way
• Kubernetes in Action. Great reference book by Mark Luksa. Read it once, digest it and come back later for a second read, plus subsequent grasps in order to retain core concepts. Note, at least in the version I took, network policies were not included and those are required for CKAD
• KodeKloud learning website with lots of practical exercises. There are great online courses, but the practical part is harder to find. I just loved this website and paid for a subscription. Kudos for Mumshad Mannambeth

Tips:

• Bash is your friend. The exam is practical on a linux terminal. If you are not fluent with vi, sed, grep, tee you will lose precious time. I could not finish both exams 100%, so losing time in bash discomfort is a challenge
• Understand&Practice. You do not have to memorize YAMLs, but trust me, if you have practiced enough, you will mostly know by heart the basic structure of apiVersion, kind, metadata, spec and should understand all properties. Kubectl explain should be your known friend
• K8S docs are available. The official kubernetes documentation is available and it has certain structure. Know how to navigate it. Another reason why you do not need to memorize
• Failing is not a disaster. You have a free retake. Although I passed both at the first real try, I had a failed attempt cancelled by a last minute customer meeting that only gave me one hour of exam. If you can do the exam in one hour, you are a pro, but for people like myself who have to work with other technologies and are not fully focused on containers, this is out of scope. I reviewed the exam structure carefully for a proper and focused second attempt that I passed. I might have struggle to pass it that easily without this initial experience
• Time engineering. I was not able to finish both exams, if I remember delivering 95% and 94% of all exam points (Questions are weighted). Go for the big fishes, if you see that a 2% question is going to take you a while, just skip it for later. There might be 9% questions that are in your area of stronger expertise waiting for you

In essence, a very enabling experience I recommend to every tech professional. Good luck