Top 30 Kubernetes Interview Questions (2026)

Core Concepts

1. What is the difference between a Pod and a Deployment?

A Pod is the smallest deployable unit in Kubernetes — one or more containers sharing network and storage. A Deployment manages a ReplicaSet which maintains a desired number of Pod replicas. Use Deployments for stateless workloads; they handle rolling updates and rollbacks automatically.

2. What happens when a node runs out of memory?

The kubelet uses the oom_score_adj Linux kernel value to prioritize which processes to kill. Pods that exceed their requests are killed first. This is why setting accurate resource requests is critical for cluster stability.

Networking

3. How does a Service route traffic to Pods?

A Service uses label selectors to find matching Pods and maintains an Endpoints object. kube-proxy on each node programs iptables/IPVS rules to forward traffic to any healthy Pod endpoint, load-balancing across replicas.