Docker Commands

This section provides a comprehensive reference for Docker commands, including common use cases and best practices.

Basic Commands

Container Management

# Run a container
docker run [OPTIONS] IMAGE [COMMAND]

# List running containers
docker ps

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

# Stop a container
docker stop CONTAINER_ID

# Remove a container
docker rm CONTAINER_ID

# Remove a running container (force)
docker rm -f CONTAINER_ID

Image Management

# List images
docker images

# Pull an image
docker pull IMAGE_NAME

# Build an image
docker build -t IMAGE_NAME .

# Remove an image
docker rmi IMAGE_NAME

Common Use Cases

Running a Web Application

# Run a web application with port mapping
docker run -d -p 8080:80 nginx

# Run with environment variables
docker run -d -e DB_HOST=db -e DB_USER=user myapp

Working with Volumes

# Create a named volume
docker volume create my_volume

# Mount a volume
docker run -v my_volume:/data myapp

# Mount a host directory
docker run -v /host/path:/container/path myapp

Networking

# Create a network
docker network create my_network

# Connect a container to a network
docker network connect my_network container_id

# List networks
docker network ls

Best Practices

  1. Use Specific Tags: Always use specific version tags instead of latest 
    docker pull nginx:1.25.3
  2. Clean Up Resources: Regularly remove unused containers, images, and volumes 
    # Remove all stopped containers
docker container prune
   
# Remove all unused images
docker image prune
   
# Remove all unused volumes
docker volume prune
  3. Use Multi-stage Builds: For smaller production images 
    # Build stage
FROM node:16 AS builder
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
RUN npm run build

# Production stage
FROM nginx:alpine
COPY --from=builder /app/build /usr/share/nginx/html
EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]

Troubleshooting

Common Issues

  1. Container Won’t Start 
    # Check container logs
docker logs CONTAINER_ID
   
# Check container details
docker inspect CONTAINER_ID
  2. Port Conflicts 
    # Check which process is using a port
lsof -i :8080
  3. Permission Issues 
    # Run container with correct user
docker run -u $(id -u):$(id -g) myapp

Additional Resources