agrozyme/docker-buildx-qemu repository overview

⁠Summary

Source: https://gitlab.com/agrozyme-docker/docker-buildx-qemu⁠

Alpine-based image with docker client, buildx, and qemu. Easily allows cross platform image builds.

⁠Description

Inspired By jonoh/docker-buildx-qemu⁠

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.

⁠Target Platforms

The Docker image can run in the environment (The intersection of Alpine and Docker Buildx support platforms):

• linux/386
• linux/amd64
• linux/arm/v6
• linux/arm/v7
• linux/arm64
• linux/ppc64le
• linux/riscv64
• linux/s390x

⁠Support Platforms

This Docker image can emulate the environments:

• linux/386
• linux/amd64
• linux/arm/v6
• linux/arm/v7
• linux/arm64
• linux/ppc64le
• linux/riscv64
• linux/s390x

⁠GitLab CI Template

It has two template files for building multi-platform Docker images.

• Single: For a single branch repository, deploy main to latest
• Multiple: Each branch is mapped to a docker image tag and the repository name is the same as Docker Registry.

⁠Docker Hub

• Single: /.gitlab/ci/single/docker-hub.yaml
• Multiple: /.gitlab/ci/multiple/docker-hub.yaml

⁠GitLab Container Registry

• Single: /.gitlab/ci/single/gitlab.yaml
• Multiple: /.gitlab/ci/multiple/gitlab.yaml

⁠Workflow:

• The main tag of the docker image is used to test the build.
• The build-one-arch job pushes the main tag of the docker image.
• When the build-one-arch job is successful, then the build-all-arch job pushes the multi-platform Docker image.
• After pushing the docker image, the build-metadata-push job will update the description of the Docker Hub repository.
  • Short description: The description of the project⁠.
  • Full description: README.md

⁠Environment variables

Put all docker image repositories into a Group and set Variables⁠ in CI / CD Settings

⁠Override priority

Put the variables in .gitlab-ci.yml or CI / CD Settings to override default.

• .gitlab-ci.yml stage variables
• .gitlab-ci.yml global variables
• Project CI / CD Settings
• Group CI / CD Settings

⁠Required

No default value, all variables are required. (Only for Docker Hub)

• DOCKER_HUB_USER: Login username
• DOCKER_HUB_PASS: Login password encoded by base64
• DOCKER_HUB_NAMESPACE:
  • username or organization
  • It will be passed to the Dockerfile as an ARG.

⁠Optional

• DOCKER_HUB_API_URL
  • The Docker Registry API url
  • Only use .gitlab-ci.yml to override
  • default: https://hub.docker.com/v2
• DOCKER_REGISTRY
  • The docker login server
  • Only use .gitlab-ci.yml to override
  • It will be passed to the Dockerfile as an ARG.
  • default: docker.io
• DOCKER_PLATFORM
  • The target platform for building docker image.
  • default: linux/amd64,linux/arm64.

⁠Hook Scripts

It has two bash scripts to hook before_script and after_script, the scripts run at beginning and end of the docker build and push action.

• before_script.sh
• after_script.sh

Note:

• If you want to download the files during the build of docker image, you can do this by writing before_script.sh and using COPY command in the Dockerfile.
• It is just done once before / after the docker buildx and you can speed up the build of multi-platform docker image.

⁠Example

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

.gitlab-ci.yml

include:
  - project: 'agrozyme-docker/docker-buildx-qemu'
    ref: main
    file: '/.gitlab/ci/single/docker-hub.yaml'

build-one-arch:
  extends:
    - .build-one-arch

build-all-arch:
  extends:
    - .build-all-arch
  needs: ['build-one-arch']

build-metadata-push:
  extends:
    - .build-metadata-push
  needs: ['build-all-arch']