What are Dockerfile multi-stage builds and how do I use them?

What are Dockerfile multi-stage builds and how do I use them?

Dockerfile multi-stage builds allow you to use multiple FROM statements in your Dockerfile. This helps in creating smaller images by separating the build environment from the runtime environment.

Can you give me an example of a multi-stage build?

Sure! Here's a simple example:

# First stage: build the application
FROM node:14 AS build
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
RUN npm run build

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

What are the benefits of using multi-stage builds?

The benefits include reduced image size, improved build times, and better separation of concerns, making your Docker images cleaner and more efficient.

Are there any limitations I should be aware of?

Yes, one limitation is that you cannot use the same build context across multiple stages. Also, be mindful of the final image size if you include unnecessary files.