I'm trying to set up a cephx key to mount RBD images read-only. I have the following two keys: [client.rbd] key = xxx caps mgr = "profile rbd" caps mon = "profile rbd" caps osd = "profile rbd pool=rbd_vm" [client.rbd-ro] key = xxx caps mgr = "profile rbd-read-only" caps mon = "profile rbd" caps osd = "profile rbd-read-only pool=rbd_vm" The following works: # rbd map --pool rbd_vm andras_test --name client.rbd /dev/rbd0 and so does this: # rbd map --pool rbd_vm andras_test --name client.rbd --read-only /dev/rbd0 but the using the rbd-ro key doesn't work: # rbd map --pool rbd_vm andras_test --name client.rbd-ro --read-only rbd: sysfs write failed In some cases useful info is found in syslog - try "dmesg | tail". rbd: map failed: (1) Operation not permitted the logs only have the following: [1281776.788709] libceph: mon4 10.128.150.14:6789 session established [1281776.801747] libceph: client88900164 fsid d7b33135-0940-4e48-8aa6-1d2026597c2f The back end of mimic 13.2.8, the kernel is the CentOS kernel 3.10.0-957.27.2.el7.x86_64 Any ideas what I'm doing wrong here? Andras