epel-release is mandatory
epel-release is mandatory

see: 2345896f14f5adddd9fd8ab14afa699b44d038d3@lists.ceph.com/msg14819.html
also: https://github.com/ceph/ceph-deploy/commit/831b130f98a18db09c862f56e80b788bbf094373

ceph/ansible-ceph-common