30+ Kubernetes Interview Questions

Google originally created Kubernetes, an open-source container orchestration technology, in 2014. The deployment, scaling, and administration of containerized applications were all intended to be automated.

Kubernetes has developed over time to become the industry’s de facto standard for container orchestration and is extensively used by businesses of all sizes to manage their workloads in containers.

The significance of Kubernetes in the modern world rests in its capacity to offer a consistent method of managing containerized applications at scale, spanning various clusters and cloud environments. Because of this, businesses can manage, expand, and deploy their applications quickly and effectively.

The maintenance of containerized apps is further made easier by Kubernetes’ extensive feature set, which includes self-healing, automated scaling, and rolling upgrades.

As more businesses use containerization and microservices to speed up their application development and deployment procedures, Kubernetes’ scope is anticipated to keep expanding in the future.

The adoption of cloud-native technologies and the general move to multi-cloud and hybrid cloud systems will both depend heavily on Kubernetes. As more and more devices are linked to the internet, Kubernetes will likewise be utilized more and more in the context of edge computing and IoT.

I assume you are already aware of these details because you are reading this post on Kubernetes Interview Questions, which will inform you of the most often-asked interview questions. Let’s begin. 

1. What is Kubernetes? 

Kubernetes is an open-source framework for containerized application orchestration and administration. It makes it possible to consistently and effectively deploy, scale, and maintain containerized applications.

Kubernetes offers a single method for managing containerized applications at scale and is built to operate across various clusters and cloud environments.

Self-healing, automated scaling, and rolling upgrades are just a few of the capabilities that make managing containerized apps even easier.

2. What do you mean by the container in Kubernetes?

Containers are a portable, lightweight, and self-sufficient approach to packaging and running software. Application packaging and deployment are done consistently and effectively in Kubernetes using containers.

In order to keep itself apart from other containers and the host machine, each container only executes one process. An application’s dependencies, libraries, and configuration files are all included in the container image that serves as the definition of a container.

A container’s intended number of replicas is always operating thanks to Kubernetes’ use of container orchestration to manage and scale the containers. This makes it simple for developers to manage and deploy their applications across several clusters and cloud environments.

3. What are the main components of Kubernetes?

Here are the main components of kubeneters:

• The Kubernetes master: This component, which also comprises the controller manager and scheduler, etcd (a distributed key-value store), the API server, and other components, is in charge of managing the cluster as a whole.
• Nodes: These are the workstations on which the containerized programs are executed. The kubelet, which interacts with the master to maintain the cluster’s intended state, is executed on each node together with a container runtime (such as Docker).
• Pods: The Kubernetes object model’s smallest and most basic element is the pod, which serves as a host for one or more containers.
• Services: Services offer a consistent endpoint for pods and enable load balancing and service discovery.
• Replication controllers: They guarantee that the required number of pod replicas are always operating.
• Secrets and ConfigMaps: These resources are used to maintain the configuration data and secrets for pods and other cluster objects.

4. What do you mean by orchestration in kubernetes?

In Kubernetes, the term “orchestration” refers to the automated administration and coordination of containers and the resources they are connected to. It involves activities including networking, scalability, deployment, and self-healing. Using objects like pods, services, and replication controllers, Kubernetes orchestrates applications.

Pods, which can hold one or more containers, are the smallest deployable units. Services manage load balancing and service discovery and give pods a solid endpoint. A replica of a pod is always operating with the required number of copies thanks to replication controllers.

5. What exactly is a Kubernetes cluster?

A set of nodes running containerized apps across diverse contexts and machines—cloud-based, physical, virtual, and on-premises—make up a Kubernetes cluster. It facilitates the simple management and migration of apps as well as their creation.

6. How is containerized deployment made simpler by Kubernetes?

Since a typical application would operate in a cluster of containers on many hosts, all of these containers would need to communicate with one another.

So, in order to accomplish this, a large-scale system that can scale, load balance, and monitor the containers is required. You must use Kubernetes to ease containerized deployment since it is cloud-agnostic and can operate on any public or private provider.

7. What fundamental distinctions exist between Kubernetes and the Docker Swarm?

Schedule and cluster Docker containers with Docker Swarm, a native, open-source container orchestration tool from Docker. The following characteristics set Swarm apart from Kubernetes:

• While Kubernetes and Docker Swarm both lack auto-scaling capabilities, Docker scaling is five times quicker than Kubernetes.
• Kubernetes provides a GUI in the form of a dashboard, but Docker Swarm lacks one.
• Compared to Kubernetes, which is more difficult to set up but offers the guarantee of a strong cluster, Docker Swarm is easier to install but does not have a stable cluster.
• While Kubernetes includes built-in capabilities for logging and monitoring, Docker needs external tools like the ELK stack.
• Rolling updates can be deployed via Docker, but automated rollbacks cannot be; Rolling updates as well as automated rollbacks can be deployed using Kubernetes.

8. What is a namespace in Kubernetes?

The Kubernetes namespace is utilized in a setting where there are several users working on numerous projects across a wide geographic area. The namespace divides the cluster resources across several users.

9. What exactly is the Kubernetes etcd master component?

Etcd is a crucial part of the Kubernetes master server. Additionally, it serves as the hub of the Kubernetes cluster, where items are stored in a distributed key-value store.

Replication technology is used in conjunction with an algorithm to preserve the data saved in etcd between servers. When comparing and swapping data between etcd servers, the optimistic currency is used to minimize locking situations and increase server speed.

10. What solutions are there for API security on Kubernetes?

Providing API Security can be done in the manner listed below:

• Via means of API authentication
• Selecting the appropriate authentication mode for the API server authentication mode= Node, RBAC
• Tracking RBAC errors
• Ensuring that TLS is being used to safeguard the traffic
• Using authorization-mode=Webhook to ensure that Kubeless safeguards its API
• Elimination of the default Service Account permissions
• Using kube’s most recent release
• Making sure that the kube-dashboard follows a stringent RBAC policy
• Implementing a pod security policy to limit container access and safeguard the node

11. What are the differences between applications deployed on hosts and containers?

An operating system and an architecture make up deployed applications. The operating system will have a kernel that houses the multiple libraries needed by an application.

A machine that runs process containers is referred to as a container host. Since this type of software is distinct from other programs, the apps must include the necessary libraries. The binaries cannot infringe on the rights of any other software since they are separated from the rest of the system.

12. What do you actually mean by Minikube?

With Minikube, Kubernetes can be easily run locally. This allows a virtual machine to host a Kubernetes cluster with a single node.

13. How can the Kubernetes cluster be monitored?

The operation and status of containers operating under Kubernetes can be tracked using a variety of methods. Prometheus, one of the most often used instruments, contains a number of parts, which are broken down in the sections below.

• The Prometheus server collects and stores time series data.
• It includes client libraries that facilitate instrumenting application code.
• It features a push gateway that can support temporary jobs.
• There are exporters with specialized functions for a variety of container services, like StatsD, HAProxy, Graphite, etc.
• Additionally, you will receive an alert manager to handle notifications on various support systems.

14. What function do Kubernetes nodes serve?

For the operation of pods, Node offers crucial functions. Nods, which are also known as minions, can operate on any real or virtual computer depending on the cluster.

In Kubernetes, the node is the primary worker computer, while master components oversee each node individually.

15. Describe the hipster in detail.

Heapster combines the data throughout the whole cluster that Kubelet, which is executed on each node, generates. This container management tool is natively supported by this Kubernetes cluster, and it functions as a pod just like any other pod in the cluster.

Basically, this entails locating every node in the cluster and utilizing an on-machine Kubernetes agent to query data from the cluster’s Kubernetes nodes.

16. Describe the operation of the Kubernetes master node.

The master node elevates the worker nodes’ ruling and controlling nodes. This is similar to a Kubernetes cluster. The nodes are in charge of cluster management as well as the API used to configure and manage the collection’s resources. Because of the benefit of dedicated pods, Kubernetes master nodes can run alongside Kubernetes itself.

17. What differentiates the container from the pod?

As a replication unit, Kubernetes utilizes a pod, which is a group of containers. Containers are the collection of codes that a pod for an application should create. Within the same pod, containers can communicate with one another.

18. What do you understand by load balancer in Kubernetes?

One of the most prevalent and accepted methods of service exposure is a load balancer. Depending on the working environment, a load balancer is either an internal load balancer or an external load balancer.

While the External Load Balancer routes traffic from the external load to the backend pods, the Internal Load Balancer automatically balances the load and assigns the pods with the necessary configuration.

19. What function does the Kube-API server perform?

For the API objects, this type verifies and offers configuration information. It consists of replication controllers, services, and pods. Additionally, it offers REST operations and the cluster’s interface. All other components communicate with one another via this common frontend cluster state.

20. What do Kubernetes’ stateful sets mean?

A workload API object called a stateful set is used to manage stateful applications. It is employed to scale the sets of pods and manage deployments. In the disc storage that links to the stateful set, the state information and other resilient data of stateful pods were saved and kept up to date.

21. How do you examine the pod’s central logs?

For retrieving central logs from the pod, you can utilize one of the two logging styles.

• Use a logging agent at the node level.
• The sidecar container in the stream
• Use the logging agent together with the sidecar container.
• Directly export the logs from the program

22. ClusterIP: What is it?

The default Kubernetes service, ClusterIP, offers an internal cluster service (with no external access) that other apps in your cluster can access.

23. Tell me about replication controllers?

For all long-running pods, replication controllers serve as supervisors. It guarantees that the required number of pods are active at any one moment and that each pod or group of pods has a consistent structure.

If there are more pods than the intended number, the surplus pods are terminated. In addition, the controller will immediately replace any faulty pods.

24. How does the Ingress network operate and what is it?

Users can access your Kubernetes services from outside the Kubernetes cluster thanks to an item called an ingress. By establishing rules that specify which inbound connections reach certain services, users can configure access.

This API object offers the routing rules needed to control how the services in the Kubernetes cluster are accessed by visitors from outside the cluster through HTTPS/HTTP. With this, users can build up the traffic routing rules quickly and efficiently without having to make several load balancers or expose every service to the nodes.

25. Prometheus in Kubernetes: what is it for?

An open-source toolkit called Prometheus is used to monitor and warn the application depending on metrics. It offers a data schema, and a query language, and is able to deliver metrics information and actions. It enables the use of language for many instrumental purposes.

In addition to Alertmanager and Grafana, the Prometheus operator offers simple monitoring for deployments and K8s services.

26. What is headless service?

A headless service is one that utilizes an IP address but gives information about connected pods rather than load balancing.

27. For running the Kubernetes architecture locally, what do I need?

For Kubernetes integration, several on-premises infrastructures have undergone remodeling. High-level expertise is needed to integrate storage, servers, and networking into a seamless system.

Selecting the appropriate networking and storage hardware is essential for Kubernetes since it enables interaction with resources for storage, load balancers, etc. Automating networking and storage components is a key component of Kubernetes’ value proposition.

28. What do you understand by Stateful set?

The workload API item known as the stateful set is utilized to manage stateful applications. It can also be used to scale the sets of pods and manage deployments. The disc storage, which is connected to the stateful set, houses the state information and other data for the stateful pods.

29. In Kubernetes, what do minions mean?

In Kubernetes, a node is referred to as a worker machine; previously, it was known as a minion. Based on a cluster, it could be a virtual computer or a real machine.

Each node is governed by Kubernetes master components and contains the services needed to operate pods. The container runtime, kubelet, and Kube-proxy are included in the services offered by the node.

30. What functions do services perform within the Kubernetes components?

Through the provision of the virtual IP address, a service serves as an abstraction for pods. The virtual IP address facilitates user connections to containers running inside pods. It is a component that determines how containers are arranged within pods.

31. What exactly is Helm?

The CNF-maintained Helm application package management registry is available for Kubernetes. The pre-configured Helm charts can be downloaded and deployed in your Kubernetes system. One of the most popular package management solutions for the Kubernetes environment is this one. DevOps teams can deploy apps into the production and development environments, version them, and track their progress using the existing charts.

32. Explain PVC

PVC is an acronym for Persistent Volume Claim. It is storage that Kubernetes has requested for pods. User knowledge of the underlying provisioning is not necessary. The namespace where the pod is formed and where this claim should be made should match.

Conclusion

The Kubernetes interview questions and answers are complete.

There is undoubtedly more to learn about Kubernetes, the cutting-edge technology that has made it feasible to manage and run thousands of containers, but this is a solid place to start. For help with interview preparation, see Hashdork’s Interview Series.