What Is Docker and How to Use It for Development

Short answer

Docker is a platform that packages applications into lightweight containers. Containers include everything needed to run the app, ensuring consistency across development and production.

How it works

Docker uses images as blueprints and containers as running instances. A Dockerfile defines the environment, dependencies, and commands. Docker Compose can orchestrate multiple containers.

Example

A simple Dockerfile:

FROM node:18
WORKDIR /app
COPY . .
RUN npm install
CMD ["node", "server.js"]

Why it matters

Docker eliminates "works on my machine" problems. Teams can share identical environments, and deployments become repeatable and scalable.