Usage of Ceph for block storage has been tested and certified with Red Hat Enterprise Linux OpenStack Enterprise Platform version 4, based on Havana. The specific version of Ceph and Cinder driver used is 0.67.5. Commercial support for this Ceph release is provided by Inktank, through their Ceph Enterprise product, version 1.1. This combination is enabled through enhancements in the qemu-kvm-rhev package, which is able to detect and use the librbd library provided by Inktank.
In addition to the librbd library, Inktank's Ceph Enterprise 1.1 depends on a number of packages that are not included in Red Hat Enterprise Linux OpenStack Platform, namely:
ceph gdisk leveldb libcephfs1 librados2 librbd1 libunwind python-ceph python-flask python-werkzeug
All these packages are provided by Inktank through their own repository. Support for these packages, including the Ceph block storage (Cinder) driver, is also provided by Inktank, in accordance with Red Hat's support policy for third party software 
Inktank does not recommend using iSCSI for creating routes to data storage entities alongside the Cinder/BlockStorage rbd driver.