ceph auth list
installed auth entries:

mds.b
	key: AQA89TpXWEfmEBAAXjtT61hGtoA6861NQRXEHA==
	caps: [mds] allow
	caps: [mon] allow rwx
	caps: [osd] allow *
i use this command then add new mds:
ceph-authtool --create-keyring --gen-key -n mds.b /etc/ceph/keyring.mds.b
ceph auth add mds.b osd 'allow *' mon 'allow rwx' mds 'allow' -i /etc/ceph/keyring.mds.b