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+---
+name: docker-management
+description: Build, optimize, and troubleshoot Docker containers and images. Create efficient Dockerfiles, manage container lifecycle, configure networking and volumes, and debug container issues. Use when working with Docker, containerization, or container troubleshooting.
+license: MIT
+metadata:
+  author: devops-skills
+  version: "1.0"
+---
+
+# 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
+
+```dockerfile
+# 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
+
+```dockerfile
+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
+
+```dockerfile
+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
+
+```bash
+# 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 .
+
+# Build with no cache
+docker build --no-cache -t myapp:fresh .
+```
+
+### Multi-Platform Builds
+
+```bash
+# Create builder
+docker buildx create --name multiplatform --use
+
+# Build for multiple architectures
+docker buildx build \
+  --platform linux/amd64,linux/arm64 \
+  -t myregistry/myapp:latest \
+  --push .
+```
+
+## Running Containers
+
+### Basic Operations
+
+```bash
+# Run container
+docker run -d --name myapp -p 8080:3000 myapp:latest
+
+# Run with environment variables
+docker run -d \
+  -e DATABASE_URL=postgres://localhost/db \
+  -e NODE_ENV=production \
+  myapp:latest
+
+# Run with resource limits
+docker run -d \
+  --memory="512m" \
+  --cpus="1.0" \
+  myapp:latest
+
+# Run with restart policy
+docker run -d --restart=unless-stopped myapp:latest
+```
+
+### Volume Management
+
+```bash
+# Named volume
+docker volume create mydata
+docker run -v mydata:/app/data myapp:latest
+
+# Bind mount
+docker run -v $(pwd)/config:/app/config:ro myapp:latest
+
+# tmpfs mount (memory)
+docker run --tmpfs /tmp:rw,noexec,nosuid myapp:latest
+```
+
+### Networking
+
+```bash
+# Create network
+docker network create mynetwork
+
+# Run on network
+docker run -d --network mynetwork --name api myapp:latest
+
+# Connect existing container
+docker network connect mynetwork existing-container
+
+# Expose specific ports
+docker run -d -p 127.0.0.1:8080:3000 myapp:latest
+```
+
+## Container Lifecycle
+
+### Management Commands
+
+```bash
+# List containers
+docker ps -a
+
+# Stop container
+docker stop myapp
+
+# Remove container
+docker rm myapp
+
+# Force remove running container
+docker rm -f myapp
+
+# Prune stopped containers
+docker container prune -f
+```
+
+### Logs and Monitoring
+
+```bash
+# View logs
+docker logs myapp
+
+# Follow logs
+docker logs -f --tail 100 myapp
+
+# View resource usage
+docker stats myapp
+
+# Inspect container
+docker inspect myapp
+```
+
+## Debugging Containers
+
+### Interactive Access
+
+```bash
+# Execute command in running container
+docker exec -it myapp /bin/sh
+
+# Run container with shell
+docker run -it --rm myapp:latest /bin/sh
+
+# Debug failed container
+docker run -it --entrypoint /bin/sh myapp:latest
+```
+
+### Troubleshooting
+
+```bash
+# Check container logs for errors
+docker logs myapp 2>&1 | grep -i error
+
+# Inspect container state
+docker inspect --format='{{.State.Status}}' myapp
+
+# Check container processes
+docker top myapp
+
+# View container filesystem changes
+docker diff myapp
+
+# Export container filesystem
+docker export myapp > myapp-fs.tar
+```
+
+### Health Checks
+
+```dockerfile
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+  CMD curl -f http://localhost:3000/health || exit 1
+```
+
+```bash
+# Check health status
+docker inspect --format='{{.State.Health.Status}}' myapp
+```
+
+## Image Management
+
+### Tagging and Pushing
+
+```bash
+# Tag image
+docker tag myapp:latest myregistry.com/myapp:v1.0
+
+# Push to registry
+docker push myregistry.com/myapp:v1.0
+
+# Pull image
+docker pull myregistry.com/myapp:v1.0
+```
+
+### Cleanup
+
+```bash
+# Remove unused images
+docker image prune -a
+
+# Remove all unused resources
+docker system prune -a --volumes
+
+# Remove specific image
+docker rmi myapp:old
+
+# List image sizes
+docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}"
+```
+
+### Image Analysis
+
+```bash
+# View image history
+docker history myapp:latest
+
+# Inspect image layers
+docker inspect myapp:latest
+
+# Check image vulnerabilities (with Docker Scout)
+docker scout cves myapp:latest
+```
+
+## Docker Compose Integration
+
+```yaml
+# docker-compose.yml
+version: '3.8'
+
+services:
+  app:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    ports:
+      - "3000:3000"
+    environment:
+      - NODE_ENV=production
+    volumes:
+      - app-data:/app/data
+    depends_on:
+      - db
+    restart: unless-stopped
+
+  db:
+    image: postgres:15-alpine
+    environment:
+      POSTGRES_PASSWORD: secret
+    volumes:
+      - db-data:/var/lib/postgresql/data
+
+volumes:
+  app-data:
+  db-data:
+```
+
+## Security Best Practices
+
+### Image Security
+
+```dockerfile
+# Use specific version tags
+FROM node:20.10-alpine3.18
+
+# Don't run as root
+USER nobody
+
+# Remove unnecessary packages
+RUN apk del --purge build-dependencies
+
+# Use COPY instead of ADD
+COPY . .
+```
+
+### Runtime Security
+
+```bash
+# Run with security options
+docker run -d \
+  --security-opt=no-new-privileges \
+  --cap-drop=ALL \
+  --cap-add=NET_BIND_SERVICE \
+  --read-only \
+  myapp:latest
+
+# Use user namespace remapping
+# Add to /etc/docker/daemon.json: {"userns-remap": "default"}
+```
+
+## Common Issues
+
+### Issue: Container Exits Immediately
+**Problem**: Container starts and stops instantly
+**Solution**: Check if CMD/ENTRYPOINT runs foreground process, use `docker logs` to see errors
+
+### Issue: Cannot Connect to Container
+**Problem**: Port not accessible
+**Solution**: Verify port mapping (-p), check container is running, verify firewall rules
+
+### Issue: Out of Disk Space
+**Problem**: Docker using too much disk
+**Solution**: Run `docker system prune -a --volumes`, check for large unused images
+
+### Issue: Build Cache Not Working
+**Problem**: Every build downloads dependencies
+**Solution**: Order Dockerfile instructions from least to most frequently changing
+
+## Best Practices
+
+- Use multi-stage builds to minimize image size
+- Never store secrets in images - use runtime injection
+- Pin base image versions for reproducibility
+- Implement health checks for production containers
+- Use .dockerignore to exclude unnecessary files
+- Run containers as non-root users
+- Scan images for vulnerabilities regularly
+- Use Docker BuildKit for faster builds
+
+## Related Skills
+
+- [docker-compose](../docker-compose/) - Multi-container applications
+- [container-scanning](../../../security/scanning/container-scanning/) - Security scanning
+- [container-hardening](../../../security/hardening/container-hardening/) - Security hardening