I've updated the Kubernetes Certificate Manager based on the dns01 exec plugins proposal. I've also pulled out all native support for DNS providers and now the Google DNS provider requires the googledns exec plugin. For ease of use the kube-cert-manager container image includes the googledns plugin, but it's easy to now build and ship your own:

https://github.com/kelseyhightower/kube-cert-manager/blob/ma...