Docker

Multi-arch Build

Builder Setup

Install QEMOU to allow emulation of different arches. Using emulation is not the most efficient way to build an image. See Docker docs for more other ways.

docker run --privileged --rm tonistiigi/binfmt --install all

Creating the new builder:

docker buildx create --name <Name> --bootstrap --use

Replace <Name> with a different name. The Flag --use will automaticity select the builder as default. Running docker buildx ls should show your new builder, with available platforms.

Building an Image

Edit your Dockerfile to select the arch depending on the build argument.

- FROM alpine:latest
+ ARG ARCH=
+ FROM ${ARCH}alpine:latest

Now you can build your image using

docker buildx build --push --platform linux/arm64/v8,linux/amd64/v3 --tag OWNER/IMAGE:VERSION .

This will build the image in the current directory for arm64 & amd64 and push it into the registry to OWNER/IMAGE:VERSION.