gcloud container clusters create --cluster-version 1.10 --zone us-east1-d ... returns with the error message ERROR: (gcloud.container.clusters.create) ResponseError: code=400, message=No valid versions with the prefix "1.10" found..
The GKE release notes https://cloud.google.com/kubernetes-engine/release-notes#february-11-2019, indicates the specific kubernetes version is still supported.
Does anyone know what's going on?
The syntax you are using looks correct, but support for k8s 1.10 is being phased out on GKE, as per the GKE release notes entry of February 11, 2019:
Coming soon
We expect the following changes in the coming weeks. This information is not a guarantee, but is provided to help you plan for upcoming changes.
25% of the upgrades from 1.10 to 1.11.6-gke.2 will be complete.
Version 1.11.6-gke.8 will be made available.
Version 1.10 will be made unavailable.
Have you tried with the full version, say 1.10.12-gke.7?
gcloud container clusters create --cluster-version 1.10.12-gke.7 --zone us-east1-d ...
Alternatively, use 1.11, because it looks like GKE is moving that way anyhow.