docker

name	docker
version	v1.0.0
last_updated	2026-04-06T00:00:00.000Z
description	Docker container management skill. Build, run, manage containers, images, networks, and volumes. Use for containerization, Docker Compose, multi-container apps, and DevOps tasks.

Docker

Docker container management for building, running, and managing containers.

Activation Keywords

• docker
• container
• docker-compose
• docker compose
• containerization
• 容器
• 镜像
• docker build
• docker run

Tools Used

• exec - Execute Docker CLI commands
• read - Read Dockerfiles, compose files
• write - Create Dockerfiles, compose files
• edit - Modify Docker configurations

Workflow Decision Tree

User Request → Identify Task Type
├── Build Image → docker build workflow
├── Run Container → docker run workflow
├── Manage Containers → docker ps/stop/rm workflow
├── Compose Multi-Container → docker compose workflow
├── Network Management → docker network workflow
├── Volume Management → docker volume workflow
└── Debug Issues → docker logs/exec workflow

Core Commands Reference

Container Management

# List running containers
docker ps

# List all containers (including stopped)
docker ps -a

# Run container
docker run -d --name <name> -p <host:container> <image>

# Run with environment variables
docker run -d --name <name> -e KEY=VALUE <image>

# Run with volume mount
docker run -d --name <name> -v /host/path:/container/path <image>

# Stop container
docker stop <container>

# Remove container
docker rm <container>

# Force remove running container
docker rm -f <container>

# Execute command in container
docker exec -it <container> <command>

# View logs
docker logs <container>
docker logs -f <container>  # follow mode
docker logs --tail 100 <container>  # last 100 lines

Image Management

# List images
docker images

# Build image from Dockerfile
docker build -t <name>:<tag> <path>
docker build -t <name>:<tag> -f <dockerfile> <path>

# Pull image
docker pull <image>:<tag>

# Push image
docker push <image>:<tag>

# Remove image
docker rmi <image>

# Remove dangling images
docker image prune

# Tag image
docker tag <source> <target>

Docker Compose

# Start services
docker compose up -d

# Stop services
docker compose down

# View logs
docker compose logs
docker compose logs -f <service>

# Restart services
docker compose restart

# Build services
docker compose build

# Execute in service
docker compose exec <service> <command>

# Scale services
docker compose up -d --scale <service>=<count>

Network Management

# List networks
docker network ls

# Create network
docker network create <name>

# Create network with driver
docker network create -d bridge <name>

# Connect container to network
docker network connect <network> <container>

# Disconnect container
docker network disconnect <network> <container>

# Remove network
docker network rm <network>

Volume Management

# List volumes
docker volume ls

# Create volume
docker volume create <name>

# Remove volume
docker volume rm <name>

# Remove unused volumes
docker volume prune

System Cleanup

# Show disk usage
docker system df

# Remove unused data
docker system prune

# Remove all unused data (images, containers, volumes)
docker system prune -a --volumes

Common Patterns

Dockerfile Template

# Use official base image
FROM python:3.11-slim

# Set working directory
WORKDIR /app

# Install dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy application
COPY . .

# Set environment variables
ENV PYTHONUNBUFFERED=1

# Expose port
EXPOSE 8000

# Run command
CMD ["python", "main.py"]

Docker Compose Template

version: '3.8'

services:
  app:
    build: .
    ports:
      - "8000:8000"
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/dbname
    volumes:
      - ./data:/app/data
    depends_on:
      - db
  
  db:
    image: postgres:15
    environment:
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=pass
      - POSTGRES_DB=dbname
    volumes:
      - postgres_data:/var/lib/postgresql/data

volumes:
  postgres_data:

Best Practices

Dockerfile

1. Use specific image tags - Avoid latest in production
2. Minimize layers - Combine RUN commands with &&
3. Use multi-stage builds - Reduce final image size
4. Leverage build cache - Order commands from least to most frequent changes
5. Use .dockerignore - Exclude unnecessary files

Security

1. Don't run as root - Add USER instruction
2. Scan images - Use docker scout or third-party tools
3. Use secrets management - Don't hardcode credentials
4. Limit resources - Use --cpus, --memory

Performance

1. Use alpine images - Smaller footprint
2. Optimize COPY order - Leverage layer caching
3. Use health checks - Add HEALTHCHECK instruction

Troubleshooting

Common Issues

1. Container won't start

   # Check logs
   docker logs <container>
   
   # Check exit code
   docker inspect <container> --format='{{.State.ExitCode}}'
   

2. Port already in use

   # Find process using port
   lsof -i :<port>
   
   # Use different host port
   docker run -p <different_port>:<container_port> <image>
   

3. Disk space issues

   # Check disk usage
   docker system df
   
   # Clean up
   docker system prune -a --volumes
   

4. Permission denied

   # Run with user namespace
   docker run --user $(id -u):$(id -g) <image>
   
   # Or fix volume permissions
   sudo chown -R $(id -u):$(id -g) /host/path
   

Examples

Run MySQL Container

docker run -d \
  --name mysql \
  -e MYSQL_ROOT_PASSWORD=rootpass \
  -e MYSQL_DATABASE=mydb \
  -p 3306:3306 \
  -v mysql_data:/var/lib/mysql \
  mysql:8.0

Run Redis Container

docker run -d \
  --name redis \
  -p 6379:6379 \
  -v redis_data:/data \
  redis:7-alpine

Run Nginx Reverse Proxy

docker run -d \
  --name nginx \
  -p 80:80 \
  -p 443:443 \
  -v ./nginx.conf:/etc/nginx/nginx.conf:ro \
  -v ./ssl:/etc/nginx/ssl:ro \
  nginx:alpine

Resources

• Docker Official Documentation
• Docker Hub
• Docker Compose Specification
• Best Practices Guide