Top Kubernetes interview questions and answers in a single article can be quite overwhelming. However, I can provide you with a selection of common Kubernetes interview questions and answers, categorized by different aspects of Kubernetes, along with a cheat sheet table to help you prepare. Let’s begin:
Kubernetes Basics
1. What is Kubernetes, and why is it used?
Answer: Kubernetes is an open-source container orchestration platform used to automate the deployment, scaling, and management of containerized applications. It helps in managing containerized applications at scale and ensures high availability, scalability, and resource efficiency.
2. Explain the key components of Kubernetes architecture.
Answer: Kubernetes has several key components, including:
| Component | Description |
|---|---|
| Master Node | Controls the cluster and schedules workloads. |
| Node/Minion/Worker Node | Runs containers and reports back to the master. |
| Pods | The smallest deployable units in Kubernetes. |
| Services | Provides network access to a set of pods. |
| Replication Controller | Ensures a specified number of pod replicas exist. |
| API Server | Exposes the Kubernetes API. |
| etcd | Consistent and highly-available key-value store. |
3. What is a Pod in Kubernetes?
Answer: A Pod is the smallest deployable unit in Kubernetes. It represents a single instance of a running process in a cluster and can contain one or more containers. Containers within the same Pod share the same network namespace, storage, and IP address.
Kubernetes Networking
4. Explain Kubernetes Service types.
Answer: Kubernetes offers different types of Services to expose applications. The common types include:
- ClusterIP: Provides internal cluster-only access.
- NodePort: Exposes the service on each node’s IP and a static port.
- LoadBalancer: Uses an external load balancer to route traffic.
- Ingress: Manages external access to services, typically HTTP.
5. What is a Kubernetes Ingress?
Answer: Kubernetes Ingress is an API object used to manage external access to services within a cluster. It allows you to define routing rules, SSL/TLS termination, and load balancing for HTTP and HTTPS traffic.
6. How does DNS work in Kubernetes?
Answer: Kubernetes provides a DNS service called kube-dns or CoreDNS, which allows pods to discover each other by DNS names. Pods can resolve other pod names by their Service names or DNS names.
Kubernetes Deployments
7. What is a Kubernetes Deployment?
Answer: A Deployment is a Kubernetes resource that manages the deployment of replica sets and pods. It enables declarative updates to applications, such as rolling updates and rollbacks.
8. Explain the difference between a Deployment and a StatefulSet.
Answer: Deployments are suitable for stateless applications, while StatefulSets are used for stateful applications where each pod has a unique identity and stable network identity. StatefulSets ensure ordered pod creation and scaling.
9. How do you perform a rolling update in Kubernetes?
Answer: To perform a rolling update in Kubernetes, you can update the Deployment’s container image or configuration. Kubernetes will automatically create new pods with the updated configuration and gradually replace the old pods.
Cheat Sheet: Kubernetes Interview Questions
Here’s a cheat sheet summarizing some key Kubernetes interview questions and answers:
| Question | Answer |
|---|---|
| What is Kubernetes and its key components? | Kubernetes is an open-source container orchestration platform with key components like the Master Node, Node, Pods, Services, etc. |
| What is a Pod in Kubernetes? | A Pod is the smallest deployable unit in Kubernetes, containing one or more containers. |
| Explain Kubernetes Service types. | Kubernetes offers ClusterIP, NodePort, LoadBalancer, and Ingress as common service types. |
| What is a Kubernetes Ingress? | Kubernetes Ingress is used for managing external access to services and routing rules. |
| How does DNS work in Kubernetes? | Kubernetes provides DNS service for pod name resolution, typically using kube-dns. |
| What is a Kubernetes Deployment? | A Deployment manages the deployment of replica sets and pods, enabling declarative updates. |
| Difference between Deployment and StatefulSet? | Deployments are for stateless apps; StatefulSets are for stateful apps with unique identities. |
| How to perform a rolling update in Kubernetes? | Update the Deployment’s configuration, and Kubernetes will replace old pods gradually. |
Remember that this is just a subset of Kubernetes interview questions. Depending on the role and level of expertise required, you may encounter more advanced questions on topics like Helm, Operators, and Kubernetes security. Be sure to study and practice these topics thoroughly before your interview.
