A few notes:

• We have Rook working via the Zonca method effectively for JupyterHub
  • https://arxiv.org/pdf/1805.04781.pdf
• We now have Rook shared storage via flexVolume thanks to Rook
• We know that GCE Filers support NFS, SMB and Gluster
  • https://cloud.google.com/solutions/filers-on-compute-engine

• We know that EFS supports NFSv4 (and probably SMB
• We know that AzureDisk supports SMB
• We've discussed two broad options
  • Try and get rook running everywhere (OpenStack, AWS, GCE, Azure)
  • Replace current GlusterFS with NFS and rely on existing fileservers 
• EFS appears to be the only ReadWriteMany storage option with PVC support

Getting rook running everywhere

• This is no problem for Openstack, but would require some work/thinking around how to provision different instance groups with attached storage, etc.

Using NFS everywhere:

• Should work for AWS via EFS or GCE via file server.  Unclear whether NFS will work with AzureDisk.
  • See also GCE example for Jupyterhub using filer https://cloud.google.com/solutions/using-tensorflow-jupyterhub-classrooms
• Will require work to deploy fileserver via terraform for OpenStack.