Docker Basics

Essential Docker commands for everyday container management.

Container Lifecycle

# Run a container
docker run nginx

# Run in detached mode
docker run -d nginx

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

# Run with name
docker run -d --name my-nginx nginx

# Run with environment variables
docker run -d -e MY_VAR=value nginx

# Run with volume mount
docker run -d -v /host/path:/container/path nginx

Managing Containers

# List running containers
docker ps

# List all containers
docker ps -a

# Stop a container
docker stop container_name

# Start a stopped container
docker start container_name

# Restart a container
docker restart container_name

# Remove a container
docker rm container_name

# Force remove running container
docker rm -f container_name

Container Interaction

# Execute command in container
docker exec -it container_name bash

# View container logs
docker logs container_name

# Follow logs
docker logs -f container_name

# Copy files to/from container
docker cp file.txt container_name:/path/
docker cp container_name:/path/file.txt ./

Example Dockerfile

FROM node:18-alpine

WORKDIR /app

COPY package*.json ./
RUN npm ci --only=production

COPY . .

EXPOSE 3000

CMD ["node", "server.js"]

Building and Running from Dockerfile

# Build image from Dockerfile in current directory
docker build -t my-app:latest .

# Build with a specific Dockerfile
docker build -f Dockerfile.prod -t my-app:prod .

# Build with build arguments
docker build --build-arg NODE_ENV=production -t my-app .

# Build without cache
docker build --no-cache -t my-app .

# Run the built image
docker run -d -p 3000:3000 --name my-app my-app:latest

# Tag and push to registry
docker tag my-app:latest registry.example.com/my-app:latest
docker push registry.example.com/my-app:latest

Cleanup

# Remove all stopped containers
docker container prune

# Remove unused images
docker image prune

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

# Check disk usage
docker system df