As we add DCN support in RHOSO, we want to extend the storage support to non-ceph certified third party support. 

The limitations we had in pre RHOSO such as Cinder A/A, moving back control services to central and the solid support from glance multi-stores backed by Cinder, we have all the core pieces to support non ceph backend with DCN.

Key aspects to be refined

• Same key principles
  • One backend per site
  • One AZ per site incl central
  • One cinder backend per site (not A/A)
  • One glance store per site with Central as hub
  • Same latency requirement
• Certified cinder drivers only
• Glance backed by cinder
• Assess latencies issue as there will be more data path operations between central and edge
• Nova ephemeral only
• Review Cinder Image-Volume cache to speed up boot from volume
• Glance cache not possible since OCP not running at edge
• Add manila to the picture

Since we won't be able to test every possible protocol (NFS, iscsi, FC, etc) or every possible backend, we need to find a support agreement with partners to understand if they're ok to support this design.

We also need to find a default non ceph backend to test the solution with.

There should not be any core openstack gaps but we need to check if there is any operator work needed to deploy this architecture.