Google recently deploys new fixes which ensured the kubeadmconfig Secret is deleted when a Cluster API node is removed. Added preflight check command (bmctl check preflight) that you can use when upgrading version 1.13 and higher clusters. Updated the commands bmctl check preflight and bmctl create cluster so that they fail if worker or control-plane nodes have docker credentials in /root/.docker/config.json. (Anthos clusters on bare metal version 1.13 and higher can no longer use Docker Engine as a container runtime. All clusters must use the default container runtime containerd).