SKILL.md
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:
Guide
Contents
Multi-Stage Builds
Optimization Techniques
Security Best Practices, Environment Configuration
Docker Compose for Multi-Container
Docker Compose for Multi-Container
.dockerignore File
Python (Django/Flask), Java (Spring Boot), Go
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