Kubernetes is now a core skill for DevOps, SRE, platform and cloud engineering roles. Interviewers test both architecture knowledge and your ability to troubleshoot real problems. Here are the most common Kubernetes interview questions with concise answers.
Architecture
What are the main Kubernetes components?
The control plane includes the API server, etcd (cluster state store), scheduler and controller manager. Worker nodes run the kubelet, a container runtime and kube-proxy.
What does etcd do?
It is a distributed key-value store holding the entire cluster state. Backing it up is critical for self-managed clusters.
What happens when you run kubectl apply?
The request goes to the API server, is validated and stored in etcd; controllers reconcile desired state; the scheduler assigns Pods to nodes; the kubelet starts containers.
Workloads
Pod vs. Deployment vs. StatefulSet vs. DaemonSet?
A Pod runs one or more containers. A Deployment manages stateless replicas and rolling updates. A StatefulSet provides stable identities and storage for stateful apps. A DaemonSet runs one Pod per node (logging or monitoring agents). Jobs and CronJobs run batch tasks.
What are liveness, readiness and startup probes?
Liveness restarts unhealthy containers. Readiness controls whether a Pod receives traffic. Startup probes protect slow-starting apps from premature restarts.
Networking
Service types?
ClusterIP (internal), NodePort (port on each node), LoadBalancer (cloud load balancer) and ExternalName (DNS alias).
What is an Ingress?
A set of HTTP routing rules handled by an ingress controller to expose multiple services through one entry point, with TLS termination. The newer Gateway API offers a more expressive alternative.
What are Network Policies?
Rules controlling which Pods can communicate, enforced by the network plugin (CNI).
Configuration and storage
ConfigMap vs. Secret?
ConfigMaps hold non-sensitive configuration; Secrets hold sensitive data (base64-encoded, so enable encryption at rest and consider external secret managers).
What are PersistentVolumes and PersistentVolumeClaims?
A PV is a piece of storage; a PVC is a request for storage. StorageClasses provision volumes dynamically.
Scaling and scheduling
How does autoscaling work?
The Horizontal Pod Autoscaler scales replicas based on metrics; the Vertical Pod Autoscaler adjusts resource requests; the Cluster Autoscaler or Karpenter adds and removes nodes.
Requests vs. limits?
Requests are what the scheduler reserves; limits cap usage. Exceeding a memory limit kills the container (OOMKilled); exceeding CPU limits throttles it.
Taints, tolerations and affinity?
Taints repel Pods from nodes unless they tolerate them. Node and Pod affinity rules attract Pods to specific nodes or co-locate/separate them.
Security
- RBAC with Roles, ClusterRoles and bindings for least privilege
- Service accounts and workload identity for cloud access
- Pod Security Standards (restricted, baseline)
- Image scanning and signed images
- Network Policies and secrets encryption
Troubleshooting scenarios
- Pod in CrashLoopBackOff: check logs (including previous), describe events, configuration, probes and resource limits.
- Pod stuck in Pending: insufficient resources, node selectors, taints or unbound PVCs.
- ImagePullBackOff: wrong image name/tag or missing registry credentials.
- Service not reachable: check selectors match Pod labels, endpoints exist, ports align and Network Policies allow traffic.
- Node NotReady: check kubelet status, disk/memory pressure and networking.
Practice these in a local cluster. The CKA certification is excellent preparation, and our DevOps interview questions cover the surrounding tooling.
Frequently asked questions
Is Kubernetes hard to learn for interviews?
It has many concepts, but focusing on workloads, Services, configuration, scaling and troubleshooting covers most interview questions.
Do I need the CKA to get a Kubernetes job?
No, but the CKA is respected because it is hands-on and proves practical skills.
What Kubernetes commands should I know?
kubectl get, describe, logs, exec, apply, rollout status/undo, top and port-forward are essential.
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