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Multi-platform Docker builds

Build linux/amd64 and linux/arm64 images natively on their own architecture and push a single manifest list.

Specifications

Strategy
Native per-arch, no QEMU
Output
OCI manifest list
Speedup vs QEMU
5× – 40×

Runner labels

  • runnerhut-docker-builder
  • runnerhut-docker-builder-arm

There are two ways to produce a multi-arch image. One emulates arm64 on an x64 host with QEMU and is catastrophically slow for anything that compiles. The other builds each architecture on its own hardware and stitches the results into a manifest list.

yaml
jobs:
  build:
    strategy:
      matrix:
        include:
          - platform: linux/amd64
            runner: runnerhut-8vcpu-ubuntu-2404
          - platform: linux/arm64
            runner: runnerhut-8vcpu-ubuntu-2404-arm
    runs-on: ${{ matrix.runner }}
    steps:
      - uses: docker/build-push-action@v6
        with:
          platforms: ${{ matrix.platform }}
          outputs: type=image,push-by-digest=true
 
  merge:
    needs: build
    runs-on: runnerhut-2vcpu-ubuntu-2404
    steps:
      - run: docker buildx imagetools create -t ghcr.io/acme/api:latest \
          ghcr.io/acme/api@${{ needs.build.outputs.digest }}
Build per-arch by digest, then merge

Your next build could be twice as fast, at half the price

Start free. Migrating away is the same one line, and we publish that diff too.

Start buildingSee pricing

Related

Docker builder machine specificationsHardware, attach time and cache behaviour of the persistent BuildKit instances your jobs connect to.Native arm64 GitHub Actions runnersNative Ampere and Graviton-class arm64 runners. No QEMU, no emulation penalty, 20% cheaper than the x64 equivalent.