How to fix ERROR: failed to solve: failed to push: unsupported platform in Docker

# Create and switch to a new builder with multi-platform support
docker buildx create --name multiplatform-builder --driver docker-container --use

# Verify the builder is active and supports multiple platforms
docker buildx inspect --bootstrap

# List all builders to confirm
docker buildx ls

# Install QEMU using Docker's official image (works on any Linux/Docker Desktop)
docker run --privileged --rm tonistiigi/binfmt --install all

# Verify QEMU handlers are registered
docker run --privileged --rm tonistiigi/binfmt

# On Ubuntu/Debian, you can also install via apt
sudo apt-get update
sudo apt-get install -y qemu-user-static binfmt-support

# Check available emulation targets
ls /proc/sys/fs/binfmt_misc/qemu-*

# WRONG: --load doesn't work with multi-platform
docker buildx build --platform linux/amd64,linux/arm64 --load -t myimage:latest .
# Error: docker exporter does not currently support exporting manifest lists

# CORRECT: Push directly to registry
docker buildx build --platform linux/amd64,linux/arm64 --push -t myregistry/myimage:latest .

# Or push to local registry for testing
docker run -d -p 5000:5000 --name registry registry:2
docker buildx build --platform linux/amd64,linux/arm64 --push -t localhost:5000/myimage:latest .

# Now you can use --load with multi-platform (on supported setups)
docker buildx build --platform linux/amd64,linux/arm64 --load -t myimage:latest .

# Inspect current builder capabilities
docker buildx inspect --bootstrap

# Expected output includes:
# Platforms: linux/amd64, linux/amd64/v2, linux/arm64, linux/arm/v7, ...

# If platforms are missing, recreate with explicit platform support
docker buildx create --name mybuilder --driver docker-container \
  --platform linux/amd64,linux/arm64,linux/arm/v7 --use

docker buildx inspect --bootstrap

# Login to Docker Hub
docker login

# Login to other registries
docker login ghcr.io
docker login your-private-registry.com

# Verify authentication works
docker buildx build --platform linux/amd64,linux/arm64 \
  --push -t ghcr.io/username/myimage:latest .

name: Build Multi-Platform Image

on:
  push:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          platforms: linux/amd64,linux/arm64
          push: true
          tags: username/myimage:latest