instruction: Explain Building images
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  Building images
  Building container images is both technical and an art. You want to keep the
  image small and focused to increase your security posture, but also need to
  balance potential tradeoffs, such as caching impacts. In this series, youâll
  deep dive into the secrets of images, how they are built and best practices.
  Skill level
  Beginner
  Time to complete
  25 minutes
  Prerequisites
  None
  About this series
  Learn how to build production-ready images that are lean and efficient Docker
  images, essential for minimizing overhead and enhancing deployment in
  production environments.
  What you'll learn
  Understanding image layers
  Writing a Dockerfile
  Build, tag and publish an image
  Using the build cache
  Multi-stage builds
  Modules
  1. Understanding the image layers
  Have you ever wondered how images work? This guide will help you to
  understand image layers - the fundamental building blocks of container
  images. You'll gain a comprehensive understanding of how layers are created,
  stacked, and utilized to ensure efficient and optimized containers.
  Start
  2. Writing a Dockerfile
  Mastering Dockerfile practices is vital for leveraging container technology
  effectively, enhancing application reliability and supporting DevOps and
  CI/CD methodologies. In this guide, youâll learn how to write a Dockerfile,
  how to define a base image and setup instructions, including software
  installation and copying necessary files.
  Start
  3. Build, tag, and publish an image
  Building, tagging, and publishing Docker images are key steps in the
  containerization workflow. In this guide, youâll learn how to create Docker
  images, how to tag those images with a unique identifier, and how to publish
  your image to a public registry.
  Start
  4. Using the build cache
  Using the build cache effectively allows you to achieve faster builds by
  reusing results from previous builds and skipping unnecessary steps. To
  maximize cache usage and avoid resource-intensive and time-consuming
  rebuilds, it's crucial to understand how cache invalidation works. In this
  guide, youâll learn how to use the Docker build cache efficiently for
  streamlined Docker image development and continuous integration workflows.
  Start
  5. Multi-stage builds
  By separating the build environment from the final runtime environment, you
  can significantly reduce the image size and attack surface. In this guide,
  you'll unlock the power of multi-stage builds to create lean and efficient
  Docker images, essential for minimizing overhead and enhancing deployment in
  production environments.
  Start
  
  ## Example Dockerfile
  
  ```dockerfile
  # Use official base image
  FROM node:16-alpine
  
  # Set working directory
  WORKDIR /app
  
  # Copy and install dependencies
  COPY package*.json ./
  RUN npm ci --only=production
  
  # Copy application code
  COPY . .
  
  # Expose port
  EXPOSE 3000
  
  # Health check
  HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:3000/health || exit 1
  
  # Run application
  CMD ["npm start"]
  ```
  
  ## Docker Compose Example
  
  ```yaml
  version: '3.8'
  services:
    app:
      build: .
      ports:
        - "3000:3000"
      environment:
        - NODE_ENV=production
      volumes:
        - ./data:/app/data
      restart: unless-stopped
  ```