Comment 2 for bug 1578484

Please see the Jewel release notes [1] regarding this change. Specifically, Ceph, by default, creates new RBD images using features currently unsupported by krbd. You can disable these features on an existing image using the 'rbd feature disable' command or you can revert to pre-Jewel features for all new images by adding "rbd default features = 1" in your Ceph configuration file.

[1] http://docs.ceph.com/docs/master/release-notes/#upgrading-from-infernalis-or-hammer