This tool makes what the OP is trying to do much easier: https://github.com/GoogleCloudPlatform/gke-autoneg-controller https://github.com/GoogleCloudPlatform/gk

This tool makes what the OP is trying to do much easier: https://github.com/GoogleCloudPlatform/gke-autoneg-controller https://github.com/GoogleCloudPlatform/gke-autoneg-controlle... you can have GKE configure the NEG on the BS directly, and not have to interrogate K8s for the name of the NEG to add to the BS via terraform.