As Kubernetes continues to gain popularity, knowledge of this container orchestration platform has become a sought-after skill in the tech industry. Whether you are a seasoned Kubernetes pro or just getting started, it is essential to know the answers to the following questions commonly asked in Kubernetes interview questions.
Important Kubernetes Interview Questions
If you’re preparing for a Kubernetes interview, you must have a solid understanding of the fundamental concepts and components of the platform. Here are 25 important Kubernetes interview questions to help you prepare:
- What is etcd, and what role does it play in a Kubernetes cluster?
- What is the difference between Kubernetes deployment and Kubernetes StatefulSets?
- What is a Kubernetes ingress? How is it used?
- How do you handle secrets and configuration management in Kubernetes?
- What is a Kubernetes network policy? How does it work?
- How do you automate Kubernetes deployments?
- How do you scale Kubernetes applications horizontally and vertically?
- What is the difference between a Kubernetes namespace and a label?
- What is the difference between a Kubernetes Daemonset and a Kubernetes Statefulset?
- What is a Kubernetes custom resource? How does it work?
- What is a storage class in Kubernetes? How is it used?
- How do you handle storage in Kubernetes? What are the various types of storage you can use?
- What is a Kubernetes controller? Name a few different types of controllers.
- How does Kubernetes handle load balancing and network traffic routing?
- What is a Kubernetes Secret, and how is it different from a Kubernetes ConfigMap?
- How do you deploy a stateful application in Kubernetes?
- What is a Kubernetes deployment rollout strategy? Name a few different types of strategies.
- How does Kubernetes handle security and access control? What are some best practices for securing a Kubernetes cluster?
- What is a Kubernetes Operator, and how is it used?
- What is the role of a Service Mesh, and why would you use one?
- What is a Kubernetes ConfigMap? How is it different from a Kubernetes Secret?
- How do you manage resource requests and limits in Kubernetes?
- What is aHelm Chart, and how can it help with application deployment?
- What is the difference between Deployment and Daemonset?
- What is a Kubernetes CRD (Custom Resource Definition), and how can you use it to extend Kubernetes functionality?
1. What is etcd, and what role does it play in a Kubernetes cluster?
Etcd is a distributed key-value store that stores the configuration data of a Kubernetes cluster. It is primarily used to store the state of the cluster and provides a reliable source of truth for cluster consistency. In a production environment, it is recommended to have an etcd cluster with a minimum of three nodes for high availability.
2. What is the difference between Kubernetes deployment and Kubernetes StatefulSets?
A Kubernetes deployment is suitable for stateless applications, while a Statefulset is ideal for stateful applications like databases. A deployment is designed to handle simple scaling and zero downtime rolling updates. In contrast, a Statefulset offers more guarantees on the ordering and uniqueness of pods and persistent storage.
3. What is a Kubernetes ingress? How is it used?
A Kubernetes ingress is an API object that allows external traffic to be routed to the appropriate Kubernetes services based on the incoming request’s URL or host. It is used to expose HTTP and HTTPS routes to the Kubernetes cluster.
4. How do you handle secrets and configuration management in Kubernetes?
Kubernetes provides a built-in secret’s API resource for securely storing sensitive information such as passwords, API keys, and other confidential data. Kubernetes also allows for configuration management using config maps, which can be used to store non-sensitive configuration data as key-value pairs
Also, read comprehensively about Kubernetes Secrets Security Issues.
5. What is a Kubernetes network policy? How does it work?
A Kubernetes network policy is a specification that defines how groups of pods can communicate with each other and with the outside world. It is used to enforce network traffic rules that restrict access to pods based on their labels or namespaces. Network policies use selectors and rules to allow or deny incoming or outgoing traffic between pods.
Also, read comprehensively about Best Practices for Kubernetes Network Security.
Also, read comprehensively about Kubernetes Pod Security Policies.
6. How do you automate Kubernetes deployments?
Kubernetes deployments can be automated using various tools such as Helm, Kubernetes Operators, or GitOps workflows. Helm is a package manager for Kubernetes that allows users to define, install, and upgrade Kubernetes applications. While Kubernetes Operators are a Kubernetes-native way of automating application management, GitOps relies on Git as the source of truth for defining and deploying Kubernetes applications.
7. How do you scale Kubernetes applications horizontally and vertically?
Scaling Kubernetes applications can be done horizontally or vertically. Horizontal scaling involves adding more replicas of the application, while vertical scaling increases the resources of the individual pod. Kubernetes supports both types of scaling, and it can be easily achieved by modifying the replica count or resource limits of a deployment or Statefulset.
8. What is the difference between a Kubernetes namespace and a label?
A Kubernetes namespace is a way to divide cluster resources between multiple users or teams. It provides a way to isolate resources and prevent naming conflicts. On the other hand, Kubernetes labels are key-value pairs attached to Kubernetes objects to help identify and organize them.
9. What is the difference between a Kubernetes Daemonset and a Kubernetes Statefulset?
Both Kubernetes Daemonsets and Statefulsets are used to manage pods, but they have different use cases. Daemonsets are used for running pods on every node in a cluster, while Statefulsets are used for deploying stable, ordered pods with unique network identities.
10. What is a Kubernetes custom resource? How does it work?
A Kubernetes custom resource is an extension of the Kubernetes API, providing a way to define and manage custom resources using Kubernetes-compliant tools and APIs. Custom resources can be used to manage applications and resources that are not native to Kubernetes.
11. What is a storage class in Kubernetes? How is it used?
Answer: A storage class is a Kubernetes object that defines the type of storage that can be used by a pod or a persistent volume claim (PVC). Storage classes are used to dynamically provision storage resources based on the requirements of the application.
12. How do you handle storage in Kubernetes? What are the various types of storage you can use?
Answer: Kubernetes provides several options for handling storage, including local storage, hostPath volumes, network-attached storage (NAS), and cloud-based storage. Each option has its pros and cons depending on the specific use case.
13. What is a Kubernetes controller? Name a few different types of controllers.
Answer: A Kubernetes controller is a control loop that watches over a desired state of a Kubernetes object and takes action to ensure the current state matches the desired state. Some common types of controllers include ReplicaSet, Deployment, Statefulset, and Daemonset.
14. How does Kubernetes handle load balancing and network traffic routing?
Answer: Kubernetes uses a Service object to handle load balancing and network traffic routing. A Service provides a single IP address and DNS name for a set of pods and routes traffic to those pods based on a set of rules defined by the user.
15. What is a Kubernetes secret, and how is it different from a Kubernetes configuration map?
Answer: A Kubernetes secret is an object used to store sensitive information, such as a password or API key. A configuration map, on the other hand, is used to store configuration data that a pod or container can consume.
16. How do you deploy a stateful application in Kubernetes?
Answer: Deploying a stateful application in Kubernetes requires using Statefulsets, which provides guarantees around the ordering and uniqueness of pod startup and termination.
17. What is a Kubernetes deployment rollout strategy? Name a few different types of strategies.
Answer: A Kubernetes deployment rollout strategy is used to update a deployed application to a new version. Some common deployment strategies include RollingUpdate, Recreate, and Blue/Green.
18. How does Kubernetes handle security and access control? What are some best practices for securing a Kubernetes cluster?
Answer: Kubernetes provides several built-in security features, such as role-based access control (RBAC), pod security policies, and network policies. Best practices for securing a Kubernetes cluster include applying security updates regularly, using strong authentication and access controls, and using network segmentation to separate resources.
Also, read comprehensively about Best Kubernetes Authentication Methods
Also, read comprehensively about Automating Security in Kubernetes Pipelines.
19. What is a Kubernetes Operator, and how is it used?
Answer: A Kubernetes Operator is a method for packaging, deploying, and managing Kubernetes-native applications. An Operator defines a set of custom resources and controllers to automate the management of complex applications.
20. What is the role of a Kubernetes Service Mesh, and why would you use one?
Answer: A Service Mesh is a dedicated infrastructure layer designed to manage service-to-service communication within a Kubernetes cluster. Service Meshes provide authentication, authorization, and observability features for distributed systems.
21. What is a Kubernetes ConfigMap? How is it different from a Kubernetes Secret?
Answer: A Kubernetes ConfigMap is an object used to store configuration data that a pod or container can consume. On the other hand, a Kubernetes Secret is used to store sensitive information, such as a password or API key.
22. How do you manage resource requests and limits in Kubernetes?
Answer: Kubernetes provides several mechanisms for managing resource requests and limits, including Pod resource requests and limits, and the Kubernetes Horizontal Pod Autoscaler.
23. What is a Kubernetes Helm Chart, and how can it help with application deployment?
Answer: A Kubernetes Helm Chart is a collection of Kubernetes manifest files packaged together in a single archive. Helm Charts can simplify application deployment and management by providing a standard way to package and version applications.
24. What is the difference between a Kubernetes deployment and a Kubernetes Daemonset?
Answer: A Kubernetes deployment manages a set of identical replicas of a defined application instance. It ensures that the desired number of replicas are running and monitors their health. Deployments manage the creation, update, and scaling of pods, which are the basic units in Kubernetes.
On the other hand, a Kubernetes Daemonset ensures that all the nodes in a cluster run a copy of a specific pod. A Daemonset controller creates pods on each node in the cluster and then monitors them to ensure they are healthy. Daemonsets are helpful for deploying cluster-level applications such as log collectors and monitoring agents.
In summary, a Kubernetes deployment is used to manage multiple identical replica pods while a Kubernetes Daemonset is used to ensure that a specific pod runs on all nodes in a cluster.
25. What is a Kubernetes CRD (Custom Resource Definition), and how can you use it to extend Kubernetes functionality?
Answer: A Custom Resource Definition (CRD) is used to create new Kubernetes resources unavailable in the Kubernetes core. It is a way of extending Kubernetes functionality by defining custom resources that can be used to create Kubernetes objects, such as pods, services, and deployments.
Custom resources can represent any Kubernetes object type and can be used to create custom controllers that programmatically manage these resources. For example, you can create a CRD for a custom application load balancer and then use a custom controller to manage the load balancer.
In summary, a Kubernetes CRD allows you to create custom resources that extend Kubernetes functionality beyond its core features. You can use custom resources to create custom controllers that manage these resources programmatically.
Conclusion
These are just ten of the many Kubernetes questions you may face in an interview. To become a Kubernetes expert, it is fundamental to have a good grasp of the platform’s architecture, deployment strategies, and best practices. Our security certifications are an excellent way to deepen your understanding of Kubernetes and help you stand out in job interviews. Sign up today to get started!
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