Kubernetes, from Docker to Cluster.

Kubernetes is a system that runs your app across a group of computers, restarts it when something breaks, and scales it when traffic grows — so you do not babysit each machine.

Overview
The whole picture
Kubernetes Cluster — the campus Control Plane — the office Worker Node 1 — a computer Worker Node 2 — a computer recipe saves the plan places and watches uses the app forwards work forwards work holds holds Docker Image the recipe You browser or phone The Manager places and heals Cluster Memory the written plan Service stable front desk Pod A running copy 1 Container the packed app Pod B running copy 2 Container the packed app
Outside the cluster
Control plane
Service
Pods and containers
100%

How the pieces nest

  • Docker packs the app into a Container that runs the same everywhere
  • A Pod holds that Container — the smallest unit Kubernetes will place
  • A Worker Node is one computer; the Cluster is the whole campus plus the office

What the neighbors do

  • Control Plane: places Pods, restarts crashes, keeps the written plan
  • Service: a stable front desk so you never hunt for a Pod
  • Image is the recipe; a Container is one running copy of it

Why this exists

  • A computer fails: work moves to another Worker Node
  • Traffic grows: more Pods start from the same Docker Image
  • You keep calling one Service while Pods are replaced behind it