Docker for Beginners: Containerize Your Applications

Docker simplifies development and deployment. Let's learn the basics.

What is Docker?

Docker packages your application with all its dependencies into a container that runs consistently anywhere.

Basic Concepts

• Image: Blueprint for containers
• Container: Running instance of an image
• Dockerfile: Instructions to build an image
• Docker Compose: Multi-container orchestration

Your First Dockerfile

FROM node:18-alpine

WORKDIR /app

COPY package*.json ./
RUN npm install

COPY . .

EXPOSE 3000

CMD ["npm", "start"]

Build and Run

# Build image
docker build -t my-app .

# Run container
docker run -p 3000:3000 my-app

Docker Compose

version: '3.8'
services:
  app:
    build: .
    ports:
      - "3000:3000"
  db:
    image: postgres:15
    environment:
      POSTGRES_PASSWORD: secret

Start everything: docker-compose up

Conclusion

Docker is essential for modern development. Start containerizing today!