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name docker-multi-platform
description Multi-architecture builds, buildx builder configuration, manifest lists, platform targeting, and cross-compilation patterns.
standards-version 1.6.3

Docker Multi-Platform Builds

Trigger

Use this skill when:

  • Building Docker images for multiple CPU architectures (amd64, arm64, armv7, s390x)
  • Configuring buildx builders for multi-platform output
  • Creating or managing manifest lists for multi-arch image distribution
  • Setting up CI/CD pipelines that produce multi-platform images
  • Troubleshooting cross-compilation or platform-specific build failures
  • Optimizing build cache for multi-platform workflows

Required Inputs

  • Target platforms (e.g. linux/amd64, linux/arm64)
  • Dockerfile path and build context
  • Registry destination (if pushing multi-platform images)
  • Builder driver preference (docker-container, kubernetes, remote)

Workflow

  1. Assess platform requirements - determine which architectures the image must support
  2. Configure builder - create or select a buildx builder with the right driver
  3. Prepare Dockerfile - ensure platform-agnostic instructions or use TARGETPLATFORM / TARGETARCH ARGs
  4. Build - run docker buildx build --platform with appropriate cache and output options
  5. Verify - inspect the resulting manifest list to confirm all platforms are present
  6. Distribute - push to registry or use docker buildx imagetools to combine images

Key References

  • docker buildx build --platform linux/amd64,linux/arm64 - the core multi-platform build command
  • docker buildx create --driver docker-container - create a builder capable of multi-platform
  • docker buildx ls - verify available builders and their platform support
  • docker manifest create / annotate / push - manual manifest list management
  • TARGETPLATFORM, TARGETARCH, TARGETOS, TARGETVARIANT - automatic ARGs available in Dockerfiles during cross-builds

Example Interaction

User: I need my Go API image to run on both amd64 and arm64. How do I set that up?

Assistant: Here's the approach:

  1. Create a buildx builder with docker-container driver (supports multi-platform):
docker buildx create --name multiarch --driver docker-container --use
  1. Use a multi-stage Dockerfile with cross-compilation:
FROM --platform=$BUILDPLATFORM golang:1.22-alpine AS builder
ARG TARGETARCH
WORKDIR /app
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOARCH=$TARGETARCH go build -o /api .

FROM alpine:3.20
COPY --from=builder /api /api
ENTRYPOINT ["/api"]
  1. Build and push for both platforms:
docker buildx build --platform linux/amd64,linux/arm64 \
  --tag myregistry/api:latest --push .
  1. Verify the manifest:
docker manifest inspect myregistry/api:latest

MCP Usage

This skill leverages the following MCP tools:

  • docker_buildxBuild - run multi-platform builds with cache and provenance options
  • docker_buildxLs - list builders and check platform support
  • docker_buildxCreate - create a builder with the right driver for multi-platform
  • docker_buildxRm - clean up builders no longer needed
  • docker_buildxInspect - check builder status and supported platforms
  • docker_buildxUse - switch between builders
  • docker_buildxImagetools - inspect and create manifest lists via buildx
  • docker_builderPrune - clean build cache
  • docker_manifestCreate - create manifest lists manually
  • docker_manifestInspect - verify manifest list contents and platforms
  • docker_manifestAnnotate - set platform metadata on manifest entries
  • docker_manifestPush - push manifest lists to registries
  • docker_manifestRm - remove local manifest lists
  • docker_build - single-platform builds (for comparison or fallback)

Common Pitfalls

  • Using docker build instead of docker buildx build - the regular docker build cannot produce multi-platform images. You need buildx with a docker-container or remote driver.
  • Default builder lacks multi-platform - the default docker driver only builds for the host architecture. Create a builder with --driver docker-container.
  • Architecture-specific commands in Dockerfile - hardcoded wget URLs with amd64 in the path, or architecture-specific binaries, break on other platforms. Use TARGETARCH ARG.
  • Missing QEMU for emulated builds - cross-architecture builds need QEMU registered. Run docker run --privileged --rm tonistiigi/binfmt --install all first.
  • --push vs --load - multi-platform builds cannot use --load (which loads into local Docker). Use --push to a registry, or build one platform at a time with --load.
  • No cache configuration - multi-platform builds are slow. Use --cache-from and --cache-to with registry or local cache backends.
  • Forgetting --platform in FROM - in multi-stage builds, the build stage should use FROM --platform=$BUILDPLATFORM to run on the host architecture for speed, while the runtime stage inherits the target platform.

See Also