Add note to docs about overcloud node names being required

If the kayobe overcloud provision command is executed with overcloud
ironic nodes without names, cloud-init will fail with the following
Traceback when the deployed image boots:

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/cloudinit/sources/__init__.py", line 447, in find_source
    if s.get_data():
  File "/usr/lib/python2.7/site-packages/cloudinit/sources/__init__.py", line 132, in get_data
    self._get_standardized_metadata())
  File "/usr/lib/python2.7/site-packages/cloudinit/sources/__init__.py", line 110, in _get_standardized_metadata
    'local-hostname': self.get_hostname(),
  File "/usr/lib/python2.7/site-packages/cloudinit/sources/__init__.py", line 317, in get_hostname
    if util.is_ipv4(lhost):
  File "/usr/lib/python2.7/site-packages/cloudinit/util.py", line 544, in is_ipv4
    toks = instr.split('.')

This is a bug [1] in cloud-init. The symptom is that hosts provision
successfully, but are not accessible via SSH. A solution is to ensure
that all nodes are named.

Until we have a release of CentOS with the cloud-init fix included, we
should at least mention this limitation in our documentation.

[1] https://bugs.launchpad.net/cloud-init/+bug/1852100

Change-Id: If54f56fb9f0b626d9fae80db622b0feeae5464b9
Story: 2006832
Task: 37405

doc/source/deployment.rst

@@ -231,6 +231,8 @@ Leave the seed VM and return to the shell on the Ansible control host::
 Overcloud
 =========
 
+.. _deployment-discovery:
+
 Discovery
 ---------
 
@@ -257,7 +259,7 @@ the following on the seed::
 
     $ docker exec -it bifrost_deploy bash
     (bifrost_deploy) $ source env-vars
-    (bifrost_deploy) $ ironic node-list
+    (bifrost_deploy) $ openstack baremetal node list
 
 In order to interact with these nodes using Kayobe, run the following command
 to add them to the Kayobe and Kolla-Ansible inventories::
@@ -307,6 +309,19 @@ properties and root device hints.  To perform manual hardware inspection::
 Provisioning
 ------------
 
+.. note::
+
+   There is a `cloud-init issue
+   <https://storyboard.openstack.org/#!/story/2006832>`__ which prevents Ironic
+   nodes without names from being accessed via SSH after provisioning. To avoid
+   this issue, ensure that all Ironic nodes in the Bifrost inventory are named.
+   This may be achieved via :ref:`autodiscovery <deployment-discovery>`, or
+   manually, e.g. from the seed::
+
+       $ docker exec -it bifrost_deploy bash
+       (bifrost_deploy) $ source env-vars
+       (bifrost_deploy) $ openstack baremetal node set ee77b4ca-8860-4003-a18f-b00d01295bda --name controller0
+
 Provisioning of the overcloud is performed by the ironic service running in the
 bifrost container on the seed.  To provision the overcloud nodes::