Google Kubernetes Engine Interview Questions and Answers for 2 years experience

1. What is Kubernetes?

   • Answer: Kubernetes is an open-source container orchestration system for automating deployment, scaling, and management of containerized applications. It groups containers that make up an application into logical units for easy management and discovery.

2. What are Pods in Kubernetes?

   • Answer: Pods are the smallest and simplest units in the Kubernetes object model that you create or deploy. A pod represents a running process in Kubernetes and typically contains one or more containers, along with shared storage and network resources.

3. Explain Deployments in Kubernetes.

   • Answer: Deployments provide declarative updates for Pods and manage their lifecycle. They ensure a desired number of Pods are running, handle rolling updates and rollbacks, and manage updates without downtime.

4. What are StatefulSets in Kubernetes?

   • Answer: StatefulSets manage stateful applications, which require persistent storage and stable network identities. Unlike Deployments, StatefulSets guarantee a stable network identity for each Pod and persistent storage.

5. Describe Kubernetes Services.

   • Answer: Kubernetes Services expose a set of Pods as a network service. They provide a stable IP address and DNS name, even if the underlying Pods are replaced or scaled.

6. What are Ingress Controllers?

   • Answer: Ingress Controllers manage external access to services in a Kubernetes cluster. They act as a reverse proxy and load balancer, routing external traffic to the appropriate services based on rules defined in an Ingress resource.

7. Explain Namespaces in Kubernetes.

   • Answer: Namespaces provide a way to logically separate resources within a Kubernetes cluster. They help organize resources, improve security, and facilitate multi-tenancy.

8. What are ConfigMaps and Secrets in Kubernetes?

   • Answer: ConfigMaps store non-sensitive configuration data, while Secrets store sensitive information like passwords and API keys. Both are used to decouple configuration data from application code.

9. How does Kubernetes handle scaling?

   • Answer: Kubernetes automatically scales applications based on resource utilization or custom metrics. Deployments and StatefulSets can be configured with horizontal pod autoscalers (HPA) to automatically adjust the number of Pods based on CPU usage, memory usage, or custom metrics.

10. Explain Kubernetes Persistent Volumes (PVs) and Persistent Volume Claims (PVCs).

    • Answer: PVs represent storage that Kubernetes can manage, while PVCs are requests from Pods for storage. PVCs are bound to PVs to provide persistent storage for stateful applications.

11. What are Kubernetes Jobs?

    • Answer: Kubernetes Jobs run a specified number of Pods to completion. They are suitable for batch processing or one-time tasks.

12. What are CronJobs in Kubernetes?

    • Answer: CronJobs schedule Jobs to run periodically based on a cron expression, similar to cron jobs in Unix-like systems.

13. Describe Kubernetes DaemonSets.

    • Answer: DaemonSets ensure that every Node in a cluster runs a copy of a Pod. They are useful for running daemons or system-level services.

14. What are Nodes in Kubernetes?

    • Answer: Nodes are the worker machines in a Kubernetes cluster. They run Pods and provide the computing resources for applications.

15. Explain the concept of Kubernetes control plane.

    • Answer: The Kubernetes control plane is responsible for managing the state of the cluster, scheduling Pods, and maintaining the desired state of the cluster. It includes components like the kube-apiserver, kube-scheduler, and kube-controller-manager.

16. What is kubectl?

    • Answer: Kubectl is the command-line tool for interacting with a Kubernetes cluster. It's used to manage and monitor Kubernetes resources.

17. How do you troubleshoot a Pod that is not running?

    • Answer: Check the Pod's logs using `kubectl logs `, examine the events using `kubectl describe pod `, and check the Node's status for any resource constraints or issues.

18. Explain rolling updates in Kubernetes.

    • Answer: Rolling updates gradually replace old Pods with new ones, minimizing downtime. Deployments typically manage rolling updates.

19. What are the different types of Kubernetes Services?

    • Answer: ClusterIP (internal), NodePort (external via node ports), LoadBalancer (cloud provider load balancer), and ExternalName (maps to an external DNS name).

20. How do you expose a Kubernetes service externally?

    • Answer: Using a LoadBalancer service type (cloud-provider dependent), a NodePort service type, or an Ingress controller.

21. What are the benefits of using Google Kubernetes Engine (GKE)?

    • Answer: Managed Kubernetes service, scalability, high availability, built-in security features, integration with other Google Cloud services.

22. Explain GKE Autopilot.

    • Answer: GKE Autopilot is a fully managed Kubernetes node pool that simplifies cluster management. Google handles node provisioning, scaling, and maintenance.

23. How do you manage secrets securely in GKE?

    • Answer: Use Kubernetes Secrets, Google Cloud Secret Manager integration, and consider using strong encryption and access control policies.

24. Describe GKE's networking features.

    • Answer: GKE offers features like VPC networking, internal load balancing, and advanced networking options for improved security and performance.

25. How do you monitor your GKE cluster?

    • Answer: Use Google Cloud Monitoring, logging, and other monitoring tools to track resource usage, application performance, and cluster health.

26. Explain GKE node pools.

    • Answer: Node pools are groups of nodes with identical configurations (e.g., machine type, operating system). They allow for flexibility in managing resources and scaling.

27. How do you manage GKE cluster upgrades?

    • Answer: GKE automates many aspects of upgrades, but you can control the upgrade process and schedule maintenance windows.

28. What are GKE node auto-provisioning?

    • Answer: GKE auto-provisioning automatically scales the number of nodes based on demand, ensuring sufficient resources are available to meet application needs.

29. Explain GKE's role-based access control (RBAC).

    • Answer: RBAC allows granular control over access to Kubernetes resources by assigning roles and permissions to users and groups.

30. How do you manage cluster networking policies in GKE?

    • Answer: Using Kubernetes NetworkPolicies to control traffic flow between Pods.

31. Describe GKE's integration with other Google Cloud services.

    • Answer: Seamless integration with services like Cloud SQL, Cloud Storage, Cloud Logging, Cloud Monitoring, and more.

32. How do you troubleshoot connectivity issues in GKE?

    • Answer: Check network policies, service configurations, pod logs, and network connectivity within the VPC.

33. Explain how to back up and restore your GKE cluster.

    • Answer: Strategies include using tools like Velero or backing up persistent volumes to cloud storage.

34. What are the different authentication methods in GKE?

    • Answer: Google Cloud IAM integration, service accounts, and custom authentication methods.

35. How do you manage and scale your applications using GKE?

    • Answer: Using Deployments, StatefulSets, Horizontal Pod Autoscalers, and other Kubernetes features for automated scaling and updates.

36. Describe the different logging and monitoring tools you can use with GKE.

    • Answer: Google Cloud Logging, Google Cloud Monitoring, Prometheus, Grafana, and other monitoring and logging solutions.

37. What are the best practices for securing a GKE cluster?

    • Answer: Use RBAC, NetworkPolicies, restrict access to the cluster, regularly patch nodes and components, and leverage GKE's security features.

38. Explain how to troubleshoot performance issues in GKE.

    • Answer: Analyze resource utilization metrics, identify bottlenecks, check network latency, and optimize application code and configurations.

39. How do you handle resource requests and limits in GKE?

    • Answer: Configure resource requests and limits for Pods to ensure proper resource allocation and prevent resource starvation.

40. What is the difference between a node pool and a node group in GKE?

    • Answer: In GKE, the terms are often used interchangeably. There's no strict distinction; both refer to a group of nodes with similar characteristics.

41. Describe the different ways to deploy applications to GKE.

    • Answer: Using `kubectl apply`, Helm, GitOps tools like Argo CD, and CI/CD pipelines.

42. How do you manage and troubleshoot network connectivity between pods in different namespaces?

    • Answer: Use NetworkPolicies to allow or deny traffic between namespaces. Check NetworkPolicy configurations and use `kubectl describe` to understand network connectivity.

43. Explain how to integrate GKE with a CI/CD pipeline.

    • Answer: Use tools like Jenkins, GitLab CI, CircleCI, or Google Cloud Build to automate the build, testing, and deployment process to GKE.

44. What are the different ways to scale a GKE cluster?

    • Answer: Manually scaling node pools, using Horizontal Pod Autoscaling (HPA), and configuring cluster autoscaler for automated scaling.

45. How do you manage different versions of your application running in GKE?

    • Answer: Use deployments with multiple revisions, canary deployments, or blue/green deployments.

46. Explain the concept of Pod affinity and anti-affinity in GKE.

    • Answer: Pod affinity schedules Pods on the same Node, while Pod anti-affinity schedules them on different Nodes for high availability and fault tolerance.

47. How do you manage and monitor the health of your GKE cluster?

    • Answer: Use GKE's built-in monitoring tools, along with other monitoring solutions, to track node health, resource utilization, and application performance.

48. Describe the different ways to troubleshoot and debug applications running in GKE.

    • Answer: Use `kubectl logs`, examine events, use debuggers, and leverage monitoring and logging tools.

49. What are the best practices for cost optimization in GKE?

    • Answer: Right-sizing nodes, using preemptible VMs, optimizing resource requests and limits, and utilizing autoscaling effectively.

50. Explain how to use Helm charts to deploy applications to GKE.

    • Answer: Use `helm install` to deploy pre-packaged Kubernetes applications defined in Helm charts.

51. Describe the different ways to configure and manage persistent storage in GKE.

    • Answer: Using Google Cloud Persistent Disk, Cloud Storage buckets, and other persistent storage options.

52. How do you manage and update the Kubernetes components in a GKE cluster?

    • Answer: GKE handles most Kubernetes component upgrades automatically. You can control the upgrade process through GKE's settings.

53. Explain how to use Istio or Linkerd for service mesh in GKE.

    • Answer: Install Istio or Linkerd in your GKE cluster to enhance service discovery, traffic management, security, and observability for microservices.

54. Describe your experience with managing and troubleshooting networking issues in GKE.

    • Answer: (This requires a personal answer based on experience. Mention specific troubleshooting steps, tools used, and issues resolved.)

55. Explain your experience with implementing and managing security best practices in GKE.

    • Answer: (This requires a personal answer based on experience. Mention specific security measures implemented, like RBAC, NetworkPolicies, and security audits.)

56. Describe your experience with deploying and managing complex applications in GKE.

    • Answer: (This requires a personal answer based on experience. Mention specific application deployments, challenges faced, and solutions implemented.)

57. Explain your experience with automating deployment processes in GKE using CI/CD pipelines.

    • Answer: (This requires a personal answer based on experience. Mention specific CI/CD tools used and the automation processes implemented.)

58. Describe your experience with monitoring and alerting on GKE.

    • Answer: (This requires a personal answer based on experience. Mention specific monitoring tools and alerting strategies implemented.)

59. Explain your understanding of Kubernetes resource quotas and limits. How have you used them in GKE?

    • Answer: (This requires a personal answer based on experience. Mention how you have used resource quotas and limits for resource allocation and cost control in GKE.)

60. Describe your experience with managing different GKE node pools and their configurations.

    • Answer: (This requires a personal answer based on experience. Mention specific configurations used and the reasoning behind them.)

61. How have you used Kubernetes custom resource definitions (CRDs) in GKE?

    • Answer: (This requires a personal answer based on experience. Mention any use cases of CRDs for extending Kubernetes functionality.)

62. Describe your experience with troubleshooting and resolving issues related to Kubernetes storage in GKE.

    • Answer: (This requires a personal answer based on experience. Mention specific storage-related issues faced and the troubleshooting steps taken.)

63. How have you used GitOps principles in managing your GKE clusters?

    • Answer: (This requires a personal answer based on experience. Mention specific GitOps tools and how they were used to manage GKE.)

64. Explain your experience with automating backups and restores of your GKE deployments.

    • Answer: (This requires a personal answer based on experience. Mention specific backup and restore strategies and tools used.)

65. Describe a time when you had to debug a complex issue in your GKE cluster. What was the issue, and how did you resolve it?

    • Answer: (This requires a personal answer based on experience. Provide a detailed explanation of the issue, your troubleshooting steps, and the final resolution.)

66. What are your preferred methods for monitoring the health and performance of applications running on GKE?

    • Answer: (This requires a personal answer based on experience. Mention specific monitoring tools and metrics used.)

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