Docker Management

Build, run, and manage Docker containers for application deployment and development.

When to Use This Skill

Use this skill when:

• Creating and optimizing Dockerfiles
• Building and tagging Docker images
• Running and managing containers
• Debugging container issues
• Configuring Docker networking and volumes
• Implementing container security best practices

Prerequisites

• Docker Engine installed (20.10+)
• Basic command line knowledge
• Understanding of application deployment

Dockerfile Best Practices

Multi-Stage Build

# Build stage
FROM node:20-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
RUN npm run build

# Production stage
FROM node:20-alpine AS production
WORKDIR /app
RUN addgroup -g 1001 -S nodejs && \
    adduser -S nodejs -u 1001
COPY --from=builder --chown=nodejs:nodejs /app/dist ./dist
COPY --from=builder --chown=nodejs:nodejs /app/node_modules ./node_modules
USER nodejs
EXPOSE 3000
CMD ["node", "dist/index.js"]

Layer Optimization

FROM python:3.12-slim

# Install dependencies first (cached unless requirements change)
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy application code (changes frequently)
COPY . .

CMD ["python", "app.py"]

Security Hardening

FROM node:20-alpine

# Create non-root user
RUN addgroup -g 1001 appgroup && \
    adduser -u 1001 -G appgroup -D appuser

WORKDIR /app

# Copy with proper ownership
COPY --chown=appuser:appgroup . .

# Drop privileges
USER appuser

# Use exec form for proper signal handling
CMD ["node", "server.js"]

Building Images

Basic Build

# Build with tag
docker build -t myapp:1.0 .

# Build with build args
docker build --build-arg NODE_ENV=production -t myapp:prod .

# Build for specific platform
docker build --platform linux/amd64 -t myapp:amd64 .