Make defaults from roles_data.yaml more robust

The previous logic left out the default Count completely when it was
zero, which breaks nested validation and it's likely similar problems
would exist with the other optional defaults, so rework it so the
defaulting happens in the jinja2 logic, and document the interfaces
better in roles_data.yaml

Change-Id: I7f2eb4a3a0b43c5d2cd0d001ed3c73f783c95c74
Closes-Bug: #1625760

1 files changed, 4 insertions, 6 deletions

diff --git a/overcloud.j2.yaml b/overcloud.j2.yaml
index 187741ff..aad1af62 100644
--- a/overcloud.j2.yaml
+++ b/overcloud.j2.yaml
@@ -121,16 +121,12 @@ parameters:
                  resource_registry) which represent nested stacks
                  for each service that should get installed on the {{role.name}} role.
     type: comma_delimited_list
-  {% if role.ServicesDefault %}
-    default: {{role.ServicesDefault}}
-  {% endif %}
+    default: {{role.ServicesDefault|default([])}}
 
   {{role.name}}Count:
     description: Number of {{role.name}} nodes to deploy
     type: number
-  {% if role.CountDefault %}
-    default: {{role.CountDefault}}
-  {% endif %}
+    default: {{role.CountDefault|default(0)}}
 
   {{role.name}}HostnameFormat:
     type: string
@@ -140,6 +136,8 @@ parameters:
       and %stackname% is replaced with the stack name e.g overcloud
   {% if role.HostnameFormatDefault %}
     default: "{{role.HostnameFormatDefault}}"
+  {% else %}
+    default: "%stackname%-{{role.name.lower()}}-%index%"
   {% endif %}
 
   {{role.name}}RemovalPolicies: