Goal:

Introduce common configuration options at base store level which can be used/accessible as a common for all available stores.

There are multiple parameters used by the cinder store that could be made common for all configured cinder stores/backends.

 
[backend_defaults]
cinder_store_user_name = <user>
cinder_store_password = <pass>
cinder_store_project_name = <project>
cinder_store_auth_address = <keystone_endpoint>
cinder_use_multipath = True
[lvmdriver-1]
cinder_store_user_name = <user1>
cinder_volume_type = lvmdriver-1
[cephdriver-1]
cinder_volume_type = cephdriver-1

This has been already implemented in Cinder and Glance would benefit especially when it is configured in multistore with Cinder or Ceph (see the DCN use case):

• https://opendev.org/openstack/cinder/src/commit/935f08e032b31d4628881d3a053b73ed0b7b0743/cinder/opts.py#L344-L453
• Cinder doc example: https://docs.openstack.org/cinder/latest/admin/multi-backend.html#configure-shared-volume-driver-backends