Docker vs Kubernetes

Take a moment to think about this

Docker is a tool for building/running/shipping a single container — run `docker run` and one container starts up. Kubernetes is a layer that coordinates hundreds of running containers (Docker or containerd) — it manages 'which server should this run on', 'who restarts it on crash', and 'how do containers talk to each other'. Docker Compose is a tool for wiring up multiple containers for local development (kind of like a lightweight version of Kubernetes) — Kubernetes takes that same idea and scales it way up for production.

Let's connect this to a real scenario

When you're building a web app, you write a Dockerfile and build an image with `docker build` (that's Docker's job). If you want to run frontend + backend + database together locally, you can use Docker Compose. But in production, if you want to run 100 containers across 10 servers, load-balance traffic, and move containers off a failed server onto the remaining ones — that's Kubernetes's job.

Docker = container build/run tool (single container level)
Docker Compose = local multi-container orchestration (small scale)
Kubernetes = production-scale multi-server orchestration

Let's look at it together

text

Layer                What it does
--------------------------------------------------------
Dockerfile        →  How to build ONE container image
docker run         →  Run ONE container locally
docker-compose.yml →  Run a FEW containers together, locally
Kubernetes         →  Run MANY containers, across MANY servers,
                       self-healing, auto-scaling, production-grade

You should see

You should be able to distinguish the scope of Docker, Docker Compose, and Kubernetes.

5-minute try-it

For a blog site (frontend + backend + database), decide what you'd use for (1) local development and (2) production (10 servers), and write down why.

A quick word of caution

Don't assume that once you install Kubernetes, you no longer need Docker — you still need Docker (or a Docker-compatible tool) for building, tagging, and pushing images.