majiayu000 Docker Deployment Skill
Master containerizing and deploying Node.js applications with Docker for consistent, portable deployments.
Quick Start
Dockerize Node.js app in 3 steps:
- Create Dockerfile - Define container image
- Build Image -
docker build -t myapp . - Run Container -
docker run -p 3000:3000 myapp
Core Concepts
Basic Dockerfile
FROM node:18-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
EXPOSE 3000
CMD ["node", "src/index.js"]
Multi-Stage Build (Optimized)
# Build stage
FROM node:18-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
# Production stage
FROM node:18-alpine
WORKDIR /app
# Copy from builder
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app .
# Create non-root user
RUN addgroup -g 1001 -S nodejs && \
adduser -S nodejs -u 1001
USER nodejs
EXPOSE 3000
HEALTHCHECK --interval=30s --timeout=3s \
CMD node healthcheck.js || exit 1
CMD ["node", "src/index.js"]
Learning Path
Beginner (1-2 weeks)
- ✅ Understand Docker basics
- ✅ Create simple Dockerfile
- ✅ Build and run containers
- ✅ Manage volumes and networks
Intermediate (3-4 weeks)
- ✅ Multi-stage builds
- ✅ Docker Compose
- ✅ Environment variables
- ✅ Health checks
Advanced (5-6 weeks)
- ✅ Image optimization
- ✅ Production best practices
- ✅ Container orchestration
- ✅ CI/CD integration
Docker Compose
# docker-compose.yml
version: '3.8'
services:
app:
build: .
ports:
- "3000:3000"
environment:
- NODE_ENV=production
- DATABASE_URL=postgresql://db:5432/myapp
- REDIS_URL=redis://redis:6379
depends_on:
- db
- redis
restart: unless-stopped
db:
image: postgres:15-alpine
environment:
- POSTGRES_USER=myapp
- POSTGRES_PASSWORD=secret
- POSTGRES_DB=myapp
volumes:
- postgres-data:/var/lib/postgresql/data
redis:
image: redis:7-alpine
volumes:
- redis-data:/data
nginx:
image: nginx:alpine
ports:
- "80:80"
volumes:
- ./nginx.conf:/etc/nginx/nginx.conf:ro
depends_on:
- app
volumes:
postgres-data:
redis-data:
Docker Compose Commands
# Start services
docker-compose up -d
# View logs
docker-compose logs -f app
# Stop services
docker-compose down
# Rebuild images
docker-compose up -d --build
# Scale services
docker-compose up -d --scale app=3
.dockerignore
node_modules
npm-debug.log
.git
.gitignore
.env
.env.local
.vscode
*.md
tests
coverage
.github
Dockerfile
docker-compose.yml
Docker Commands
# Build image
docker build -t myapp:latest .
# Run container
docker run -d -p 3000:3000 --name myapp myapp:latest
# View logs
docker logs -f myapp
# Enter container
docker exec -it myapp sh
# Stop container
docker stop myapp
# Remove container
docker rm myapp
# List images
docker images
# Remove image
docker rmi myapp:latest
# Prune unused resources
docker system prune -a
Environment Variables
# In Dockerfile
ENV NODE_ENV=production
ENV PORT=3000
# Or in docker-compose.yml
environment:
- NODE_ENV=production
- PORT=3000
# Or from .env file
env_file:
- .env.production
Volumes for Persistence
services:
app:
volumes:
- ./logs:/app/logs # Bind mount
- node_modules:/app/node_modules # Named volume
volumes:
node_modules:
Health Checks
# In Dockerfile
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s \
CMD node healthcheck.js || exit 1
// healthcheck.js
const http = require('http');
const options = {
host: 'localhost',
port: 3000,
path: '/health',
timeout: 2000
};
const request = http.request(options, (res) => {
console.log(`STATUS: ${res.statusCode}`);
process.exit(res.statusCode === 200 ? 0 : 1);
});
request.on('error', (err) => {
console.log('ERROR:', err);
process.exit(1);
});
request.end();
Image Optimization
# Use Alpine (smaller base image)
FROM node:18-alpine # 180MB vs node:18 (1GB)
# Multi-stage build (remove build dependencies)
# Use .dockerignore (exclude unnecessary files)
# npm ci instead of npm install (faster, deterministic)
# Only production dependencies
RUN npm ci --only=production
# Combine RUN commands (fewer layers)
RUN apk add --no-cache git && \
npm ci && \
apk del git
Production Best Practices
FROM node:18-alpine
# Don't run as root
RUN addgroup -g 1001 -S nodejs && \
adduser -S nodejs -u 1001
WORKDIR /app
COPY --chown=nodejs:nodejs package*.json ./
RUN npm ci --only=production
COPY --chown=nodejs:nodejs . .
USER nodejs
# Health check
HEALTHCHECK CMD node healthcheck.js || exit 1
# Use node instead of npm start (better signal handling)
CMD ["node", "src/index.js"]
Docker Hub Deployment
# Login
docker login
# Tag image
docker tag myapp:latest username/myapp:1.0.0
docker tag myapp:latest username/myapp:latest
# Push to Docker Hub
docker push username/myapp:1.0.0
docker push username/myapp:latest
# Pull from Docker Hub
docker pull username/myapp:latest
CI/CD with GitHub Actions
name: Docker Build & Deploy
on:
push:
branches: [main]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- uses: docker/setup-buildx-action@v2
- uses: docker/login-action@v2
with:
username: ${{ secrets.DOCKER_USERNAME }}
password: ${{ secrets.DOCKER_PASSWORD }}
- uses: docker/build-push-action@v4
with:
push: true
tags: username/myapp:latest
cache-from: type=gha
cache-to: type=gha,mode=max
Common Issues & Solutions
Node modules caching
# Cache node_modules layer
COPY package*.json ./
RUN npm ci
COPY . . # This doesn't rebuild node_modules
Signal handling
# Use node directly (not npm)
CMD ["node", "src/index.js"]
# In app: Handle SIGTERM
process.on('SIGTERM', () => {
server.close(() => process.exit(0));
});
When to Use
Use Docker deployment when:
- Need consistent environments (dev, staging, prod)
- Deploying microservices
- Want easy scaling and orchestration
- Using cloud platforms (AWS, GCP, Azure)
- Implementing CI/CD pipelines
Related Skills
- Express REST API (containerize APIs)
- Database Integration (multi-container setup)
- Testing & Debugging (test in containers)
- Performance Optimization (optimize images)