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Before we start with Kubernetes interview questions, let us first understand Kubernetes. Kubernetes is a portable, extensible, open-source platform that manages containerized workloads and services. It facilitates declarative configuration and automation. It has a large ecosystem and provides services, tools, and support. Kubernetes is derived from Greek, meaning pilot or helmsman. Multinational companies such as SAP, Huawei, Open AI, and Sound cloud use Kubernetes in their day-to-day activities. The other word for Kubernetes is K8. As you are on this page, means you are already aware of the demand, and let us discuss the top 50 Kubernetes interview questions

Basic Kubernetes Interview Questions-

Q1. Why is Kubernetes in demand?

Ans– To understand the demand for Kubernetes we need to know it affects workflow

This flow chart represents how work used to be done in different eras-

Differenet era- Kubernetes Interview questions

Traditional Deployment era – Early on organizations used to run applications on physical servers. There was no way to define resource boundaries in a physical server, which caused resource allocation issues. If one resource would take up more run time, the other applications would underperform. A solution would be to run each application on a different server, which is impossible in traditional deployment.

Visualized Deployment era– Visualization was introduced as a solution. This allows the users to run multiple virtual machines (VMs) on a single physical server’s CPU. Applications can be isolated between VMs and provide a level of security as information of one application cannot be freely accessed by another application. Visualization allows better resource utilization and scalability because applications can be added and updated easily.

Container Deployment era– Containers are like VMs but have more relaxed properties to share the Operating Systems (OS) among the applications. Containers are considered lightweight. Just like VMs, containers have their filesystem, CPU, memory, process space, and more. They are decoupled from the underlying infrastructure and are portable across clouds. They are agile, can be constantly updated, and integrated, have resource isolation, and complete resource utilization.

Q2. What are the features of Kubernetes?                            

Ans- This is the primary question to be asked in the Kubernetes Interview question. The features of Kubernetes are as follows-

Kubernetes features-Kubernetes Interview questions
  • Service discovery and load balancing– Kubernetes can expose a container using the DNS or the IP address. If traffic to a container is high, Kubernetes can distribute the load balance equally and distribute the network traffic, so that the deployment is stable.
  • Storage orchestration– Kubernetes allows automatically mounting a storage system of a person’s choice. It can be local storage or cloud storage.
  • Automated rollbacks and rollouts– Kubernetes helps in controlling deployment in containers. We can change the actual state to the desired state at a controlled rate.
  • Automatic pin packing– In Kubernetes, we can provide it with a cluster of nodes that it can use to run containerized tasks. We can define how much space on the CPU each container can use, and Kubernetes will fit each container on the nodes and make the best use of the resources.
  • Self-Healing– Kubernetes can restart, replace, and kill containers that do not respond to a user-defined health check. It does not advertise the containers to clients till they are ready to serve.
  • Secret configuration and management– Kubernetes help us manage and store sensitive information such as passwords, SSH keys, and OAuth Tokens. One can deploy and use secret updates and application configurations without rebuilding your container.

Q.3 What is orchestration when it comes to software and DevOps?

AnsOrchestration is the integration of multiple services that allows one to automate and synchronize processes in a timely fashion. For example, if we have multiple processes to run and we place them in different containers, it will invariably create obstruction. Orchestration helps in such a situation by enabling all containers to seamlessly work towards a single goal.

Q.4. What is the difference between Kubernetes and Docker?

Ans– This is one of the primary questions asked in Kubernetes interview question. The difference between Kubernetes and Docker swarm can be summarized in this table-

FeaturesKubernetesDocker swarm
Installation and Cluster configurationSetup is very complicated, but once installed, setup is vigorousInstallation is very simple, but the cluster is not vigorous
GUIGUI is the Kubernetes DashboardThere is no GUI
ScalabilityHighly scalable and fast scalingDockers cannot auto-scale
Load BalancingManual intervention is needed for load balancing traffic between different containers and podsDocker swarms do auto load balancing of traffic between containers in the clusters
Rolling Updates and RollbacksCan deploy rolling updates and automatic rollbacksCan deploy automatic updates but not rollbacks
Data VolumesCan share storage volumes with the other containers in the same podCan share storage volumes with any container
Logging and MonitoringIn-built tools for logging and monitoringThird-party tools must be used for monitoring. Like ELK
Table summarizing the difference between Docker and Kubernetes

Q.5 How is Kubernetes related to Docker?

AnsDocker provides lifecycle management of containers and Docker image build run-time containers. These individual containers must communicate, Kubernetes is used for this purpose. So, Docker builds containers, and these containers communicate using Kubernetes.  The Containers running on multiple hosts can be manually linked and orchestrated by using Kubernetes.

Q.6 What is Container Orchestration?

AnsConsider a scenario where one has 7-8 microservices for an application. These microservices are put in individual containers, but they will not be able to communicate without orchestration. Container Orchestration means all services in individual containers working together to fulfill the needs of a single server.

Q.7 What is the need for Container Orchestration?

AnsThe following figure shows us the challenges without the Container Orchestration

Conatiner orchestration- Kubernetes Interview questions

We need orchestration so all services within containers can run together to fulfill the need for a single server. Without Container orchestration it will increase the cost of running services, it will be difficult to set up all services manually, scaling will be difficult and manual fixing if a node crash will lead to an increase in operational costs.

Q.8 What is the difference between deploying applications on hosts and containers?

AnsDeploying Applications consists of an architecture that has an operating system. The operating system will have a kernel that will hold various libraries installed on the operating system needed for the application.  

Container host refers to the system that runs the containerized process. This process is isolated from other applications therefore, they must have the necessary libraries. The binaries are separated from the rest of the system and cannot infringe any other services.

Q.9 How does Kubernetes simplify containerized deployment?

AnsA typical application will have a cluster of containers running across multiple hosts, and all containers will have to communicate with each other. So, we will need something big that will load, balance, scale and monitor the containers. Kubernetes is cloud-agnostic and can run on any public/private provider, so it’s a preferred choice to simplify containerized deployment.

Q.10. What are clusters in Kubernetes?

Ans- A Kubernetes cluster is a set of nodes that can run containerized applications. Containerized applications package an app with its dependencies and necessary services. They are more lightweight and flexible than virtual machines. This way Kubernetes clusters allow applications to be more easily developed, moved, managed, and run across multiple machines and environments.

Q.11 What makes up a Kubernetes Cluster?

Ans- It contains six main components

Kubernetes cluster- Kubernetes Interview Questions
  1. API Server- This serves as the REST interface of the Kubernetes control pane
  2. Scheduler– Places containers according to place requirements and metrics
  3. Controller Manager– Runs controller processes, and controls nodes, endpoint, and replication controllers.
  4. Kubelet– Ensures that containers are running in a POD by interacting with the Docket engine.
  5. Kube Proxy- It manages network connectivity and maintains network rules across nodes
  6. ETCD– Stores all cluster data.  It is a consistent and highly available Kubernetes backing store.

Q.12.  How do you work with the Kubernetes cluster?

AnsTo work with the Kubernetes cluster, one must first determine its desired state. The desired state of Kubernetes defines many operational elements including-

  1. Applications and workloads should be running
  2. Images that these applications need to use
  3. Resources that need to be provided
  4. Quantity of replicas

To define a state JSON or YAML files are used to specify the application type and number of applications needed to run the system

Q.13. What is Google Container Engine?

Ans- Google Container Engine (GCE), is an open-source management platform for Docker containers and platforms. This supports only those clusters which run within Google’s public service clouds

Q.14. What is a Heapster?

Ans– Heapster is a cluster-wide aggregator of data provided by Kubelet running on each node. This container management tool is supported on the Kubernetes cluster and it runs like a pod. It discovers all nodes in a cluster via a machine on Kubernetes.

Q.15 What is Minikube?

Ans– It is a tool that makes it easy to run Kubernetes locally. Minikube runs a single-node Kubernetes cluster inside a virtual machine.

Q.16 What is a Kubelet?

Ans– Kubelet is an agent service that runs on each node and enables the means to communicate with the Kubernetes. Kubelet works with the specification of containers provided to it in the PodSpec and makes sure they are healthy and running.

Q.17 What is Kubectl?

Ans- The platform using which we can give commands to the cluster is called Kubectl. It provides CLI the commands against the Kubernetes cluster with various ways to manage and create the Kubernetes cluster.

Q.18 What is a node in Kubernetes?

Ans– A node is Kubernetes the main working machine. They are also known as minions. It can run on a physical machine or a virtual machine. Nodes have all the necessary data to keep all the pods running. Nodes in the Kubernetes system are managed by the master.

Q.19. What are the different components of Kubernetes Architecture?

Kubernetes Architecture- Kubernetes Inetrview Questions

Ans- The main components of Kubernetes Architecture are the master node and worker node. Both have other built-in components. The master node has Kube-controller-manager, Kube-API server, Kube- scheduler, etc. The worker node has two functionsrunning on each node-Kubelet and Kube-proxy.

Q. 20. What is Kube-proxy?

Ans- They can run on every node and do simple TCP/UDP packet forwarding across the backend network service. So it’s a network proxy reflecting the services configured in Kubernetes API on each node.

Q.21 What are Daemon sets?

Ans- It’s a pod that runs only once on a host. Daemon sets are used for host layer attributes like a network or for monitoring a network.

Q.22 What is Namespace in Kubernetes?

Ans- Namespace is used for dividing cluster resources between multiple users. They are meant for multiple user teams spread across projects and provide the scope of resources.

Q.23 Name the initial namespaces from which Kubernetes starts.

Ans- The initial namespaces from which Kubernetes starts are- Default, Kube system, and Kube public.

Q.24. What is the Kubernetes Control Manager?

Ans- The controller manager is a Daemon, it is used for embedding core control loops, garbage collection, and namespace creation. It enables the running of multiple processors on the master node, even if they are compiled to run as a single process

Q.25. What are the types of controller managers?

Ans- There are 6 types of primary controller managers.

Controller managers-Kubernetes Interview Questions

Q. 26. What is etcd?

Ans- Kubernetes uses etcd as a distributed key-value store for all its data. The data also includes meta-data and configuration data and allows the nodes in the Kubernetes cluster to read and write. Etcd presents the state of the cluster at a specific moment in time and is a canonical hub for state management and cluster coordination of a cluster.

Q.27. What is NodePort?

Ans– It is the fundamental way to get external traffic directly into your service. It opens a specific node on all nodes and forwards all traffic to this port.

Q.28. What is Cluster IP?

Ans- The Cluster IP is the default Kubernetes service that provides service inside a cluster, which has no external access that other apps inside your cluster can access.

Q.29. What is LoadBalancer in Kubernetes?

Ans– It is a service used to expose services to the internet. A Network loadbalancer creates an IP address that forwards all traffic to your service.

Q.30. What is an Ingress network? How does it work?

Ans– Ingress allows users to access your Kubernetes services from outside the Kubernetes cluster. Users can configure the access that defines which connections reach the service.

How it works- An API object provides the routing rules to manage the external user’s access to the services in the Kubernetes cluster through HTTPS/HTTP. Using this the users can easily set up rules for routing traffic without creating a bunch of loadbalancers or exposing each service to the nodes.

Q.31. What are the different services in Kubernetes?

Ans- The different services in Kubernetes are – Cluster IP service, Node port service, External name creation service, and Loadbalancer service.

Q32. What is the role of the Kube-API server and Kube-scheduler?

Ans- The Kube API server follows the scale-out architecture, it is the front-end of the control panel. It exposes all the API of the Kubernetes master node components and is responsible for communication between the nodes and master components.

The Kube-scheduler is responsible for the distribution and management of the workload of the worker nodes. It selects the most suitable node to run the unscheduled pod based on resource requirement and utilization.

Q.33. What is a Headless service?

Ans- Headless service does not have a Cluster IP. This service enables us to directly reach the pods without proxy.

Q.34. What are the best security measures to take while using Kubernetes?

Ans- The best security measures are-

  1. Implementing network segmentation
  2. Define strict policy
  3. Restricting access to ETCD
  4. Log everything into the production environment
  5. Update the security environment every day
  6. Enabling auditing
  7. Defining resource data
  8. Use images from the repository only
  9. Scan continuously for security vulnerability
  10. Providing limited access to Kubernetes nodes

Q.35. What are federated clusters?

Ans- The Kubernetes clusters can be managed using federated clusters. The federated clusters achieve this by-

Cross-cluster discovery- This provides the ability to have DNS and LoadBalancer with backend from all participating clusters

Sync resource across clusters- Keeps the resource sync across multiple clusters to deploy set across multiple clusters.

Q.36. What is container resource monitoring?

Ans- It is very important for the users to understand the application performance and resource utilization at every extraction layer. Each level can be monitored, and this is called Container resource monitoring. The various tools are-

Tools of container resource monitoring-Kubernetes inetrview questions

Q.37 What is the difference between a replica set and a replication controller?

Ans- Replica set and controller do almost the same thing. Both ensure that a particular number of pods are running at any given time. The difference lies in the usage of selectors to replicate the pod. Replica-set uses set-based replicators and replication controllers use equity-based selectors.

Q.38 What does Kubernetes not do?

Ans- This can be a tricky question in the Kubernetes interview question. Kubernetes operates at the container level rather than at the hardware level. It provides some generally applicable features, such as deployment, scaling, and load balancing, and lets users integrate their logging, monitoring, and alerting solutions. Kubernetes is not monolithic, and few default solutions are optional and pluggable-

  • It aims to support various workloads, including stateless, stateful, and data-processing workloads.
  • It does not provide application-level services, such as middleware (for example, message buses), data-processing frameworks (for example, Spark), databases (for example, MySQL), cars, or cluster storage systems (for example, Ceph) as built-in services.
  • It only provides some integrations as proof of concept, and mechanisms to collect and export metrics.
  • It eliminates the need for orchestration.

Few scenario-based Kubernetes Interview Questions-

Q.39 Think of an MNC with an enormous distributed system, with many data centres, and VMs and they have employees working on multiple tasks. How will the company manage tasks with the Kubernetes tool?

Ans- MNCs create and launch thousands of containers along with tasks running across various nodes in a distributed system. They need a system that can give them scalability, agility, and DevOps for cloud-native applications. They can use Kubernetes to customize and schedule architecture to manage multiple containers. Kubernetes makes it possible to link container tasks and helps in achieving efficiency with great support for container storage and container networking solutions.

Q.40 Imagine a situation where a company wants to increase its efficiency and speed with minimal cost. How can a company achieve this?

Ans- The company can use the DevOps methodology. It can use the CI/CD pipeline, but the configurations can take a longer time to run. So, the next step after implementing CI/CD will be to set up the cloud environment. Once the cloud environment starts working, they can schedule containers on a cluster and orchestrate with the help of Kubernetes. This will save deployment time for the company and minimize cost too.

Q.41 A company built on monolithic architecture handles various products. Now the company wants to scale in today’s industry and the monolithic architecture is causing problems. How can the company shift to microservices and deploy its service containers?

Ans- As the company wants to shift from monolithic to microservices, they should start building it up piece by piece and parallelly switch configurations in the background. They can put each of these built-in services on the Kubernetes platform. Once, it works fine, the rest can be set in the Kubernetes Cluster.

Q.42 Consider a company that wants to revise its deployment methods and needs a platform that is more scalable and responsive. How can they achieve this?

Ans- To serve millions of clients the digital service customers expect, companies need a platform that is scalable and responsive. The companies need to move their private data centres to any cloud environment. They also need to implement the microservice architecture so that they can start using Docker containers. Once the base framework then we can use the orchestration platform that is Kubernetes. This will enable the autonomous in building applications and delivering them quickly.

Q.43 If a company wants to optimize the distribution of workloads by adopting new technologies how can the company achieve this distribution of resources?

Ans- The solution is Kubernetes. It makes sure resources are optimized efficiently and only those resources are used that are needed by the application. With the usage of the best container application tool, the company can achieve this seamlessly.

Multiple choice Kubernetes Interview Questions

Q.44 What is the basic operational unit of Kubernetes?

  1. Nodes
  2. Task
  3. Pod
  4. Container

Ans- Pod

Q.45 Which of the following runs each node and ensures containers are running in a pod?

  1. Kubelet
  2. Pod
  3. Scheduler
  4. ETCD

Ans- Kubelet

Q.46 Replication controllers and Deployment controllers are part of-

  1. ETCD manager
  2. API controller manager
  3. Master controller manager
  4. Kubeadm

Ans- Master controller manager

Q.47 Kubernetes was developed by-

  1. IBM
  2. Microsoft
  3. Google
  4. None of the above

Ans- Google

Q.48 Which of the following can be considered as the primary data store for Kubernetes?

  1. Node
  2. Pod
  3. ETCD
  4. Kubelet

Ans- ETCD

Q.49 What is Kubernetes?

  1. Extensible platform
  2. Open-source platform
  3. Portable platform
  4. All the above

Ans- All the above

Q.50 What are minions in the Kubernetes cluster?

  1. Worker node of cluster
  2. Docker containing service
  3. Monitoring engine
  4. Components of master node

Ans- Worker node of clusters is known as minions

Conclusion

The scope of Kubernetes is increasing day by day. Companies opting for Kubernetes are finding cost and time-efficient ways of doing work. The Kubernetes interview questions covered here are the most basic questions. Complete knowledge can only be achieved by studying Kubernetes and how it is beneficial to companies. There are many places online and offline to pursue this course. Select the ones that offer a complete 360 view of the course, with hand-on experience and placement options.

Recommended reads

Top 10 Kubernetes Courses in Bangalore

Top 12 DevOps Books

FAQs


Q.1 Who should learn Kubernetes?


Ans-Kubernetes should be learned by anyone who works in development and if you think creating containerized applications, management, and deployment is related to your field of work.

Q.2.Why should you learn Kubernetes?

Ans-Learning Kubernetes will introduce best practice approaches for configuring, running, and maintaining workload in clouds.

Q.3.Is Kubernetes difficult to learn?

Ans-Learning Kubernetes is not difficult. Implementing it the right way needs practice.

Q.4 What should I learn before Kubernetes?


Ans- One should be familiar with terminologies like Docker, Podman, Crio-O, before pursuing the Kubernetes course. My suggestion would be to at least gain in-depth knowledge of Docker before pursuing Kubernetes, to help you understand better and gain proper in-depth knowledge.

Q.5 What is the future of Kubernetes?

Ans- The future of the Kubernetes course is in custom resource definitions and abstractions on top of which Kubernetes is built and users can access it through CRD’s. Kubernetes will become a control plane for abstractions, and it is the CRD’s of these abstractions that developers should focus on

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