Docker Buildx build: which node is used for which platform

General Discussions
1

Disclaimer: this is a cross post from linux - Verify Docker Buildx build actually uses the native node - Stack Overflow (no feedback there)

How do I verify a Docker Buildx build actually uses the native node for a given platform?

I have a QEMU-base multi-platform Buildx builder called maven on x64 Linux. To that I appended a Mac Mini as native node for Arm builds.

$ docker buildx ls
NAME/NODE  DRIVER/ENDPOINT             STATUS   BUILDKIT PLATFORMS
builder    docker-container                              
  builder0 unix:///var/run/docker.sock inactive          
maven *    docker-container                              
  maven0   unix:///var/run/docker.sock running  v0.11.0  linux/amd64*, linux/amd64/v2, linux/arm64, ....
  mac-mini ssh://some-user@10.1.2.3    running  v0.11.5  linux/arm64*, linux/amd64, linux/amd64/v2, ...

When I build for Arm I want to be sure that Docker Buildx uses the native node rather than the QEMU container on the local host. As far as I know there is no debug-like output to the docker buildx build command that would reveal that information.

2

In the meantime I found out how to go about this. Documented on SO: linux - Verify Docker Buildx build actually uses the native node - Stack Overflow