README.md

docker-buildx-qemu

This Debian-slim-based image allows you to easily build cross-platform images. It's been tested with GitLab CI on gitlab.com, but it should work anywhere that docker-in-docker already works, and with a binfmt_misc enabled kernel.

The registry.gitlab.com/ix.ai/docker-buildx-qemu image supports the following architectures:

• amd64
• arm64
• arm/v7

The following additional tools are installed, to be used in your pipelines:

• curl
• git
• jq

Example Usage

This GitLab example should give you an idea of how to use the image.

Dockerfile

FROM alpine

RUN echo "Hello, my CPU architecture is $(uname -m)"

.gitlab-ci.yml

variables:
  DOCKER_TLS_CERTDIR: "/certs"
  DOCKER_CERT_PATH: "/certs/client"
  DOCKER_TLS: 'true'
  DOCKER_HOST: tcp://docker:2376/
  BUILDKIT_INLINE_CACHE: '1'
  DOCKER_DRIVER: overlay2
  CI_BUILD_ARCHS: "linux/arm/v7,linux/arm64,linux/amd64"
  CI_BUILD_IMAGE: "registry.gitlab.com/ix.ai/docker-buildx-qemu:latest"

build:
  image: $CI_BUILD_IMAGE
  stage: build
  services:
    - docker:dind
  retry: 2
  before_script:
    - echo "$CI_REGISTRY_PASSWORD" | docker login -u "$CI_REGISTRY_USER" --password-stdin $CI_REGISTRY
    - update-binfmts --enable # Important: Ensures execution of other binary formats is enabled in the kernel
    # Use docker-container driver to allow useful features (push/multi-platform)
    - docker context create MyContext
    - docker buildx create --driver docker-container --name MyContext --use MyContext
    - docker buildx inspect --bootstrap
  script:
    - docker buildx ls
    - docker buildx build --platform $CI_BUILD_ARCHS --progress plain --pull -t "$CI_REGISTRY_IMAGE" --push .
  after_script:
    - docker buildx rm

And the (partial) output:

#6 [linux/amd64 2/2] RUN echo "Hello, my CPU architecture is $(uname -m)"
#6 0.120 Hello, my CPU architecture is x86_64
#6 DONE 0.3s

#8 [linux/arm/v7 2/2] RUN echo "Hello, my CPU architecture is $(uname -m)"
#8 0.233 Hello, my CPU architecture is armv7l
#8 DONE 0.2s

Resources:

• GitLab: https://gitlab.com/ix.ai/docker-buildx-qemu
• GitHub: https://github.com/ix-ai/docker-buildx-qemu
• Docker Hub: https://hub.docker.com/r/ixdotai/docker-buildx-qemu

Registry

This image can be found on both GitLab Registry and Docker Hub:

• registry.gitlab.com/ix.ai/docker-buildx-qemu
• ixdotai/docker-buildx-qemu

Credits:

This work is based on ericvh/docker-buildx-qemu