setup-buildx-action/docs/advanced/append-nodes.md

Append additional nodes to the builder

Buildx also supports running builds on multiple machines. This is useful for building multi-platform images on native nodes for more complicated cases that are not handled by QEMU and generally have better performance or for distributing the build across multiple machines.

You can append nodes to the builder that is going to be created with the append input in the form of a YAML string document to remove limitations intrinsically linked to GitHub Actions (only string format is handled in the input fields):

Name	Type	Description
name	String	Name of the node. If empty, it is the name of the builder it belongs to, with an index number suffix. This is useful to set it if you want to modify/remove a node in an underlying step of you workflow.
endpoint	String	Docker context or endpoint of the node to add to the builder
driver-opts	List	List of additional driver-specific options
buildkitd-flags	String	Flags for buildkitd daemon
platforms	String	Fixed platforms for the node. If not empty, values take priority over the detected ones.

Here is an example using remote nodes with the remote driver and TLS authentication:

name: ci

on:
  push:

jobs:
  buildx:
    runs-on: ubuntu-latest
    steps:
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
        with:
          driver: remote
          endpoint: tcp://oneprovider:1234
          append: |
            - endpoint: tcp://graviton2:1234
              platforms: linux/arm64
            - endpoint: tcp://linuxone:1234
              platforms: linux/s390x            
        env:
          BUILDER_NODE_0_AUTH_TLS_CACERT: ${{ secrets.ONEPROVIDER_CA }}
          BUILDER_NODE_0_AUTH_TLS_CERT: ${{ secrets.ONEPROVIDER_CERT }}
          BUILDER_NODE_0_AUTH_TLS_KEY: ${{ secrets.ONEPROVIDER_KEY }}
          BUILDER_NODE_1_AUTH_TLS_CACERT: ${{ secrets.GRAVITON2_CA }}
          BUILDER_NODE_1_AUTH_TLS_CERT: ${{ secrets.GRAVITON2_CERT }}
          BUILDER_NODE_1_AUTH_TLS_KEY: ${{ secrets.GRAVITON2_KEY }}
          BUILDER_NODE_2_AUTH_TLS_CACERT: ${{ secrets.LINUXONE_CA }}
          BUILDER_NODE_2_AUTH_TLS_CERT: ${{ secrets.LINUXONE_CERT }}
          BUILDER_NODE_2_AUTH_TLS_KEY: ${{ secrets.LINUXONE_KEY }}