Merge "Add extra Ansible Variable perameter"

overcloud.j2.yaml

@@ -17,6 +17,10 @@ description: >
 # TODO(shadower): we should probably use the parameter groups to put
 # some order in here.
 parameters:
+  ExtraAnsibleHostVars:
+    default: {}
+    description: Mapping of Ansible host variable overrides.
+    type: json
 
   # Common parameters (not specific to
 {%- for network in networks if network.vip|default(false) and network.enabled|default(true) %}
@@ -1354,4 +1358,7 @@ outputs:
 {%- endfor %}
   AnsibleHostVarsMap:
     description: Map of Ansible Host variables per role
-    value: {get_attr: [AnsibleHostVars, value]}
+    value:
+      map_merge:
+      - {get_attr: [AnsibleHostVars, value]}
+      - {get_param: ExtraAnsibleHostVars}