Chapter 15: Kubernetes Introduction
15.1 Why Kubernetes after Compose
Docker Compose shines on one machine: API + DB with a YAML file (Chapters 6–7). Real teams often run many replicas across many machines, need self-heal, rolling updates, and a uniform API for deploy.
Kubernetes (k8s) is an orchestrator: you declare desired pods/services; the control plane works to match reality.
Why it matters for an Instagram-style badge API : one Compose stack on a laptop is fine for homework; a cluster manager (scheduler) that restarts a dead pod is the next mental model — even if your first cluster is tiny and local.
| Compose (single host) | Kubernetes |
|---|---|
| Great local multi-container | Designed for clusters |
| Restart policies per compose file | Deployments, probes, rolling updates |
| Simple networking on one Docker host | Services, kube-proxy, CNI (deeper later) |
You do not need EKS/AKS/GKE on day one. We use a local cluster.
Ravindra Bagale's Tip
Interview madhe "K8s = Docker" sangu naka. Docker/container runtime runs containers; Kubernetes schedules and heals them. Lakshat theva!