Docker for Developers: From Zero to Production

Docker is the standard for packaging applications. This tutorial gets you running a real app with Postgres in 25 minutes.

Install

# macOS: brew install --cask docker
# Ubuntu: sudo apt install docker.io docker-compose-v2
# Windows: download Docker Desktop
docker --version  # should be 27+

Core concepts

Your first container

docker run -d -p 80:80 --name my-nginx nginx
# -d = detached
# -p 80:80 = map host:container
# --name = give it a name
docker ps  # list running
docker logs my-nginx
docker stop my-nginx

Your first Dockerfile

FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]

docker build -t my-app:1.0 .
docker run -d -p 3000:3000 my-app:1.0

docker-compose (multi-container)

# docker-compose.yml
services:
  app:
    build: .
    ports: ["3000:3000"]
    depends_on: [db]
  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_PASSWORD: secret
    volumes:
      - pgdata:/var/lib/postgresql/data
volumes:
  pgdata:

docker compose up -d

Key takeaways

• Images are templates, containers are instances
• docker-compose is the right tool for multi-service apps
• Volumes are for persistent data