Kubernetes Interview Questions

1. What is Kubernetes and what problem does container orchestration solve?

2. What is a Pod in Kubernetes and why is it the smallest deployable unit?

3. What is the difference between a Deployment, a ReplicaSet, and a Pod?

4. What is a Kubernetes Service and what are the different service types?

5. How does Kubernetes handle scaling with the Horizontal Pod Autoscaler?

6. What is a Namespace in Kubernetes and when should you use one?

7. What is the difference between a ConfigMap and a Secret in Kubernetes?

8. How do liveness, readiness, and startup probes differ in Kubernetes?

9. What are Kubernetes labels and selectors and how are they used?

10. What is the role of the kube-scheduler and how does pod scheduling work?

11. What is the difference between a StatefulSet and a Deployment?

12. How do Persistent Volumes and Persistent Volume Claims work in Kubernetes?

13. What is an Ingress in Kubernetes and how does it differ from a Service?

14. How do resource requests and limits affect pod scheduling and eviction?

15. What is a DaemonSet and when would you use one?

16. What is the difference between rolling updates and recreate deployment strategies?

17. How does Kubernetes networking work and what is the CNI?

18. What are taints and tolerations in Kubernetes?

19. What is node affinity and pod affinity/anti-affinity?

20. How does Kubernetes handle secrets securely and what are the limitations?

21. What is a Job and a CronJob in Kubernetes?

22. What is the role of etcd in a Kubernetes cluster?

23. What is the difference between kubectl apply and kubectl create?

24. How does the Kubernetes control plane differ from worker nodes?

25. What is a Helm chart and why is Helm used?

26. How do you roll back a failed deployment in Kubernetes?

27. What is pod disruption budget and why does it matter?

28. What are init containers and how do they differ from sidecar containers?

29. How does horizontal scaling differ from vertical scaling in Kubernetes?

30. What is RBAC in Kubernetes and how do roles and role bindings work?

31. A container is OOMKilled while another is only slow — how do requests and limits cause each?

32. A pod has been Pending for ten minutes — how do you find out why the scheduler will not place it?

33. How do you triage a container stuck in CrashLoopBackOff without redeploying blindly?

34. How can a badly configured liveness or readiness probe turn a healthy service into an outage?

35. How do you drain a node safely, and what do you do when a PodDisruptionBudget blocks the eviction?

36. Traffic spikes but the HorizontalPodAutoscaler reacts late — where does the delay come from?

37. What goes wrong when you update a StatefulSet, and how do you roll one out safely?

38. How do you design least-privilege RBAC and find over-permissive bindings in an existing cluster?

39. How do you roll out a default-deny NetworkPolicy without breaking the cluster?

40. Service name lookups intermittently fail inside pods — how do you debug cluster DNS?

41. Requests fail during every rollout — how do you make pod termination graceful and zero-downtime?

42. The API server is returning 429s and controllers are lagging — how do you diagnose and contain the overload?

43. An admission webhook is blocking all writes to the cluster — how did that happen and how do you recover?

44. Pods are stuck in ImagePullBackOff on some nodes but not others — how do you find the real cause?

45. A PVC is stuck Terminating and a pod cannot mount its volume — how do you unpick storage failures?

46. How do you plan a Kubernetes minor version upgrade without breaking workloads on removed APIs?

47. Deployments in a tenant namespace stop creating pods with a quota error — how do quotas and LimitRanges interact?

48. A custom controller is hot-looping and its finalizer blocks deletion — how do you write a correct reconciler?

49. Nodes stay half-empty and the Cluster Autoscaler never removes them — what blocks scale-down?

50. How do you give pods credentials for external services without long-lived secrets in the cluster?

51. How do you design an audit policy that answers 'who changed this object' without drowning in log volume?

52. How do you debug a distroless container with no shell, without rebuilding or restarting the pod?

53. A node is under memory pressure — which pods does the kubelet evict first, and why?

54. Should you set CPU limits on Kubernetes pods, or only requests?

55. When would you use topology spread constraints instead of pod anti-affinity?

56. A rolling update is stuck with new pods Running but never Ready — how do you diagnose it, and where do readiness gates fit?

57. A namespace has been Terminating for hours — what is actually blocking it and how do you clear it safely?

58. A StatefulSet pod will not restart after its node failed — explain ordering guarantees and volume reattachment

59. The cluster feels slow and kubectl times out intermittently — how do you tell whether etcd or the API server is the problem?

60. How does pod priority and preemption work, and how can it destabilise a cluster?

61. A node has gone NotReady — how do you triage it, and what happens to its pods meanwhile?