What approaches exist to reduce the size of the final Docker image?

The following approaches are used to reduce the size of the final Docker image:

• Using minimal base images: for example, alpine instead of ubuntu or debian.
• Multi-stage builds: allows building the application in one image and copying only the necessary artifacts to the final image.
• Removing temporary files and caches: cleaning up packages, package manager caches, temporary files after installation.
• Combining RUN commands: reduces the number of image layers.
• Using .dockerignore: excludes unnecessary files from the build context.

Example of a multi-stage build:

FROM golang:1.20-alpine AS builder
WORKDIR /app
COPY . .
RUN go build -o myapp

FROM alpine
COPY --from=builder /app/myapp /myapp
CMD ["/myapp"]

This approach results in a compact image containing only what is necessary to run the application.