Comment 1 for bug 1863667

Work to make volume setup for Cinder more automagic (and possibly include ceph) is on roadmap, but isn't complete yet.

In the meantime, you should be able to setup lvm with Cinder by following the docs here: https://docs.openstack.org/cinder/stein/install/cinder-storage-install-obs.html

Note that you can include any configuration the docs mention by dropping files into /var/snap/microstack/common/etc/cinder/cinder.conf.d