Jesse here. I'm the eng manager for GKE and GKE On-Prem Storage lifecycle over at Google. For basic persistent volumes, we have working vSphere (block) support, which allows us to do a lot (including persistent/stateful services).

We also have great storage abstraction layers built into K8S - CSI, FlexVolumes, and a large suite of in-tree plugins - so adding additional ones is pretty easy.

I think you're talking about something else however - specifically scaled/distributed storage services.

We're investigating options here, though keep in mind you should have no problems running containerized storage services in GKE On-prem. They would be on top of the existing block support I mentioned above. I saw a couple comments in other threads from some vendors that sell solutions that do just that.

For storage systems that don't containerize, that is a different discussion. Happy to talk more.