You may be interested in trying GCCB with the bazel build step: https://github.com/GoogleCloudPlatform/cloud-builders/tree/m...

In a GCCB build, we volume-mount in the VM host's docker daemon socket, so you can use the docker CLI, and related CLIs, with no additional setup.

We initially tried a docker-in-docker approach here, but it was a bit too fragile. This attempt was quite some time ago, so it's possible things have improved.