+NOTE: If Ceph is installed locally on the {pve} cluster, the following is done
+automatically when adding the storage.
+
+If you use `cephx` authentication, which is enabled by default, you need to
+provide the keyring from the external Ceph cluster.
+
+To configure the storage via the CLI, you first need to make the file
+containing the keyring available. One way is to copy the file from the external
+Ceph cluster directly to one of the {pve} nodes. The following example will
+copy it to the `/root` directory of the node on which we run it:
+
+----
+# scp <external cephserver>:/etc/ceph/ceph.client.admin.keyring /root/rbd.keyring
+----
+
+Then use the `pvesm` CLI tool to configure the external RBD storage, use the
+`--keyring` parameter, which needs to be a path to the keyring file that you
+copied. For example:
+
+----
+# pvesm add rbd <name> --monhost "10.1.1.20 10.1.1.21 10.1.1.22" --content images --keyring /root/rbd.keyring
+----
+
+When configuring an external RBD storage via the GUI, you can copy and paste
+the keyring into the appropriate field.
+
+The keyring will be stored at
+
+----
+# /etc/pve/priv/ceph/<STORAGE_ID>.keyring
+----
+
+TIP: Creating a keyring with only the needed capabilities is recommend when
+connecting to an external cluster. For further information on Ceph user
+management, see the Ceph docs.footnoteref:[cephusermgmt,{cephdocs-url}/rados/operations/user-management/[Ceph User Management]]
+
+Ceph client configuration (optional)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Connecting to an external Ceph storage doesn't always allow setting
+client-specific options in the config DB on the external cluster. You can add a
+`ceph.conf` beside the Ceph keyring to change the Ceph client configuration for
+the storage.