How to Push a Multi-Arch Image Manifest From CI

A single build-push-action step with platforms set pushes one manifest list covering every architecture.

Add docker/setup-qemu-action for emulation, then set platforms: linux/amd64,linux/arm64 on docker/build-push-action. Buildx assembles the manifest list.

Steps

• Add docker/setup-qemu-action to enable arm64 emulation.
• Add docker/setup-buildx-action.
• Set platforms: linux/amd64,linux/arm64 on the build step.

Workflow

steps:
  - uses: docker/setup-qemu-action@v3
  - uses: docker/setup-buildx-action@v3
  - uses: docker/build-push-action@v6
    with:
      context: .
      push: true
      platforms: linux/amd64,linux/arm64
      tags: ghcr.io/${{ github.repository }}:latest

Gotchas

• Emulated arm64 builds are slower; use a native arm64 runner where possible.
• Consumers pulling the tag automatically get the manifest entry for their platform.

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