ceph.conf

[global]
fsid = fac3931e-2284-4d9b-9a35-0400119dbb40
mon_initial_members = ceph91
mon_host = 172.17.12.11
auth_supported = cephx
osd_journal_size = 1024
filestore_xattr_use_omap = true

steps followed

$ mkdir /etc/ceph
$ touch /etc/ceph/ceph.conf
$ fsid = uuid.uuid4()  # generate random uuid

Add the following contents in /etc/ceph/ceph.conf

[global]
fsid = fac3931e-2284-4d9b-9a35-0400119dbb40  # random uuid
mon_initial_members = <mon_hostname>
mon_host = <ip>
auth_supported = cephx
osd_journal_size = 1024
filestore_xattr_use_omap = true

Generate /etc/ceph/keyring using  ceph-authtool

$ ceph-authtool -C /etc/ceph/keyring
$ mkdir -p  /var/lib/ceph/mon/ceph-0
$ ceph-mon -i 0 --mkfs --keyring /etc/ceph/keyring
$ ceph mon add <mon_id> ip:[port]     # needs a monitor working
$ ceph-mon -i 0 --public-addr IP:PORT