Key concepts
- Pod — the smallest unit: one or more containers sharing a network namespace
- Deployment — describes the desired state (N replicas); K8s maintains it automatically
- Service — a stable network address for a set of Pods (in-cluster load balancing)
- Ingress — HTTP routing from outside the cluster
- ConfigMap / Secret — configuration and secrets decoupled from the image
When it makes sense
K8s is justified for dozens of microservices or heavy workloads. For a single app — Docker Compose or a managed PaaS (Heroku, Render, Fly.io) is simpler and cheaper.