We are working on rolling out containerd 1.1 to GKE alpha cluster. If everything goes as expected, it will be available in GKE alpha cluster soon.
Kubernetes 1.10 just came out on GKE, so I assume it should work today!
https://cloudplatform.googleblog.com/2018/05/Google-Kubernet...
(Note: I haven't personally tried this out. I also work for GCP)
We are working on rolling out containerd 1.1 to GKE alpha cluster. If everything goes as expected, it will be available in GKE alpha cluster soon.