Feature request: append builder

There are certain scenarios where QEMU performance is simply terrible.

A much performant approach is to use multiple native buildx ~builders~ nodes.

We can already do it using a bash script :

      - name: Set up Docker Buildx
        id: builder
        uses: docker/setup-buildx-action@v1

      - name: Append kubernetes buildx builder
        shell: bash
        run: |
          docker buildx create --append --name ${{ steps.builder.outputs.name }} \
          --driver kubernetes \
          --platform linux/arm64 \
          --driver-opt nodeselector=kubernetes.io/arch=arm64

Would it be possible to introduce an append boolean parameter? Eventually it could be an append_to accepting a step id (or the builder instance name from the output)

[baschny]

I created an action out of it for our particular use-case (should also work for the kubernetes case). It also loads an SSH key before if we need that.

https://github.com/marketplace/actions/append-buildx-nodes

[crazy-max]

@febus982 Sgtm. I think instead of a boolean parameter for append, it should be the name of the builder we want to append to. We should also have a platform input if we want to restrict a specific node.