Amend minor update docs for Rocky

Add the new external-update command for updating Ceph.

Change-Id: If336cd95f6ee17407b97ec17e59c98301de07a4a

_custom/custom.css

@@ -70,11 +70,11 @@
 .baremetal {background: #eef;}
 .virtual {background: #efe;}
 .ceph {background: #eff;}
-.ltom {background: #dee;}
 .mton {background: #ded;}
 .ntoo {background: #edd;}
 .otop {background: #dfb;}
 .ptoq {background: #afd;}
+.qtor {background: #dee;}
 .validations {background: #fdd;}
 .optional {background: #ffe;}
 

doc/source/install/post_deployment/package_update.rst

@@ -90,7 +90,14 @@ the OpenStack release that you currently operate, perform these steps:
 #. **Ceph update (optional)**
 
    If your environment includes Ceph managed by TripleO (i.e. *not*
-   what TripleO calls "external Ceph"), update Ceph by running:
+   what TripleO calls "external Ceph"), you'll want to update Ceph at
+   this point too. The procedure differs between Queens and Rocky
+   releases:
+
+   .. admonition:: Queens
+      :class: ptoq
+
+      Run:
 
       .. code-block:: bash
 
@@ -112,6 +119,18 @@ the OpenStack release that you currently operate, perform these steps:
       operations previously disabled by `update prepare`, and triggers
       the rolling update playbook of the Ceph installer (`ceph-ansible`).
 
+   .. admonition:: Rocky
+      :class: qtor
+
+      Run:
+
+      .. code-block:: bash
+
+         openstack overcloud external-update run --tags ceph
+
+      This will update Ceph by running ceph-ansible installer with
+      update playbook.
+
 #. **Update convergence**
 
    To finish the update procedure, run: