Multi-Stage vs. Single-Stage Docker Builds
Overview
Docker lets you build container images using instructions in a Dockerfile. There are two common approaches: Single-Stage Builds and Multi-Stage Builds. The difference lies in how much control you have over separating build dependencies from runtime.
Multi-stage builds reduce final image size by excluding unnecessary files, making production images cleaner and more secure.
Single-Stage Builds
- Everything (build tools + runtime) happens in one stage
- Faster and simpler for small projects
- Final image contains build artifacts and tools
- Can be bloated with unnecessary dependencies
Multi-Stage Builds
- Separate build and runtime environments using multiple
FROMstatements - Use aliases (e.g.,
FROM node:18 AS builder) and copy only what’s needed - Final image is slim and production-ready
- Improves security and performance by excluding build tools
- Ideal for complex projects (e.g., Node.js, Go, Java)
Comparison Table
| Aspect | Single-Stage | Multi-Stage |
|---|---|---|
| Image Size | Larger | Smaller |
| Security | Less secure (includes dev tools) | More secure (lean, minimal) |
| Build Speed | Faster for small apps | Optimized with caching |
| Best For | Quick prototypes | Production-ready apps |
| Flexibility | Low | High |
Example: Multi-Stage Dockerfile
FROM node:18 AS builder
WORKDIR /app
COPY . .
RUN npm install && npm run build
FROM nginx:alpine
COPY --from=builder /app/dist /usr/share/nginx/html