Docker Containerization

Table of Contents

• [Overview](#overview)
• [When to Use](#when-to-use)
• [Quick Start](#quick-start)
• [Reference Guides](#reference-guides)
• [Best Practices](#best-practices)

Overview

Build production-ready Docker containers following best practices for security, performance, and maintainability.

When to Use

• Containerizing applications for deployment
• Creating Dockerfiles for new services
• Optimizing existing container images
• Setting up development environments
• Building CI/CD container pipelines
• Implementing microservices

Quick Start

Minimal working example:

# Multi-stage build for Node.js application
# Stage 1: Build
FROM node:18-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
RUN npm run build

# Stage 2: Production
FROM node:18-alpine
WORKDIR /app
# Copy only production dependencies and built files
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/dist ./dist
COPY package*.json ./

# Security: Run as non-root user
RUN addgroup -g 1001 -S nodejs && adduser -S nodejs -u 1001
USER nodejs

EXPOSE 3000
CMD ["node", "dist/index.js"]

Reference Guides

Detailed implementations in the references/ directory:

Best Practices

✅ DO

• Use official base images
• Implement multi-stage builds
• Run as non-root user
• Use .dockerignore
• Pin specific versions
• Include health checks
• Scan for vulnerabilities
• Minimize layers
• Use build caching effectively

❌ DON'T

• Use 'latest' tag in production
• Run as root user
• Include secrets in images
• Create unnecessary layers
• Install unnecessary packages
• Ignore security updates
• Store data in containers