Cracking the Cognixia Interview: Insights into the Top Questions You’ll Get Asked

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Some common cloud computing interview questions were talked about in one of our previous episodes, which got a lot of good feedback. We are very glad it helped you in preparing for your interviews. So, this week, we are back with one more interview questions and answers episode. In today’s episode, we will discuss some common questions you may encounter in a Kubernetes technical interview.

Before we begin, let us quickly take a look at what is Kubernetes. Kubernetes is an open-source distributed technology that is used for scheduling and executing containers in and across clusters. People use it all the time to organize containers, and it’s pretty much the standard term for it. The way the market stands, if you are building containerized applications, you would be using Kubernetes for sure.

If someone asks you about this simple definition during your interview, you can use it. However, most interviewers would be more interested in how well you know how to use Kubernetes technically, not in such basic definitions. However, this still gets asked sometimes, so better go prepared, right?.

So, now let us look at some commonly asked Kubernetes interview questions. We have a candidate X and the interviewing manager Y.

X: Sure, Y. I am excited about this, this is a very good opportunity for me.

X: There are two commands which are commonly used for carrying out maintenance activities on Kubernetes nodes. First, the kubectl cordon followed by the kubectl drain – ignore-daemon set. The first command would either move the node to a maintenance node or make it unavailable. Next, a kubectl drain would be run, which would remove the pods from the node. Once the drain command has been successfully executed, maintenance activities can be safely performed.

Y: And what if I need to carry out the maintenance activities on only a single pod?

X: In that case, I would use two more commands: kubectl get nodes to see a list of all the nodes and kubectl drain to remove all the resources from a specific node.

As soon as security patches are released, the Kubernetes administrator must perform the maintenance task to apply the patch to the running container in order to protect it from vulnerabilities. This is an unavoidable part of the Kubernetes administration.

X: I would use limits and requests for controlling the resource usage of the pod. Using the request function, I would set a limit on how many resources the pod could ask for. If it went over that limit, it would be slowed down to its request. If I use the limit function, I can tell a container how many resources it can use at most. For any container that tries to go over this limit, Kubernetes can end the container if it thinks that another container needs those resources more.

X: In that case, I think the total resource capacity for the cluster should be less than or equal to the sum of all the resource limits for containers.

Y: Good. That makes sense. So, tell me, what is a init container and when can I use it?.

It helps users get ready to run the pod before they do so with an init container. In order to get the most out of the init container, you should wait a while before starting the application container with a command like sleep 60. I would also recommend cloning a git repository into a volume.

Y: Good, good. You seem to know your concepts well. Could you tell me the role of load balancing in Kubernetes?.

X: Sure, Y. Load balancing is a way to distribute the incoming traffic into multiple back-end servers. It’s helpful to make sure that other users can access the app, which is what the name means: balancing the load.

X: I have four main recommendations for increasing Kubernetes security. This would involve limiting the communication between pods and setting up appropriate network policies. I would recommend role-based access control to narrow down the permissions to the users. I would recommend using namespaces to establish security boundaries. I also think you should set the admission control policies so that the privileged containers don’t run, and finally, you should turn on audit logging.

X: Sure, Y. Prometheus is an essential tool for Kubernetes monitoring. The Prometheus server scrapes and stores the time-series data. It has client libraries for instrumenting application code, a push gateway to help with short-lived jobs, and some exporters for StatsD, HAProxy, Graphite, and other services. , and most importantly, an alert manager for handling the support tools.

Y: That’s very good. You mentioned namespaces. Why would you use namespaces? And, what about using the default namespace?.

X: Namespaces help you keep track of blue/green environments because each namespace can have a different version of an app and share resources that are in any other namespace. Namespaces are also helpful when more than one team needs to use the same cluster without interfering with each other. If you only use the default namespace, it will be hard to see all of the applications that are being managed in the cluster over time. Overall, namespaces make it easier to organize the applications into groups that make sense. So, I do recommend using namespaces.

X: Managing Kubernetes apps isn’t always as simple and straightforward as managing stateless apps, despite what you might think. For stateful applications, upgrading each replica would need a different set of handling methods because each replica would be in a different state. This raises the need for a human operator – the Kubernetes operator who would manage these stateful applications. The Kubernetes operator also helps automate a standard process on multiple Kubernetes clusters.

X: I would use a Minikube tool for this. The tool runs a single-node bunch in a virtual machine on the computer.

Y: That’s good. That’s all I have for now. I think I have a good idea of where you stand with Kubernetes. The recruiter will get back to you with the next steps.

X: Thank you for your time today, Y. I am looking forward to hearing from the recruiter.

And, folks, those were some of the important questions that commonly get asked in a Kubernetes technical interview. Are you ready for the next step in your career and want to improve your Kubernetes skills? Come to Cognixia! As the world’s leading digital talent transformation company, we offer a top-notch Docker and Kubernetes training and certification program that will help you learn all the important concepts and skills you need to do well in a Kubernetes career. The program is 100% live virtual instructor-led, making sure you can attend the program from anywhere. This online course from Cognixia covers everything you need to know about Docker and Kubernetes, including how to run Kubernetes instances on Minikube, work with Kubernetes clusters, change workloads, use the Kubernetes API for specialized workloads, scale deployments and application security, and understand the whole container ecosystem. So, get started today!.

With that, we come to the end of this week’s podcast episode. Until next week then! Stay safe and happy learning, folks!.

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