Features
- Package applications with all dependencies into containers
- Consistent environments from dev to production
- Docker Compose for multi-container applications
- Massive ecosystem of pre-built images on Docker Hub
Pros
- Eliminates 'works on my machine' problems
- Industry standard for application packaging
- Excellent isolation between services
Cons
- Adds complexity to local development setup
- Image size management requires attention
- Performance overhead on macOS and Windows
Overview
Docker is the industry-standard containerization platform that packages applications and their dependencies into lightweight, portable containers. A Docker container includes everything needed to run an application: code, runtime, system tools, and libraries, ensuring it behaves identically regardless of where it runs.
Docker uses a Dockerfile to define the build steps for a container image, and Docker Compose to orchestrate multi-container applications (like a web server + database + cache). This declarative approach makes environments reproducible and sharable across teams.
Docker has fundamentally changed how software is developed, tested, and deployed. It is the foundation for container orchestration platforms like Kubernetes and is supported by every major cloud provider and CI/CD platform.
When to Use
Use Docker when you need reproducible environments across development, staging, and production. It is essential for microservices architectures and is the standard packaging format for deploying to Kubernetes and most modern platforms.
Getting Started
FROM node:20-slim
WORKDIR /app
COPY package*.json ./
RUN npm ci --production
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]docker build -t my-app .
docker run -p 3000:3000 my-app