Add {{role.name}}RemovalPoliciesMode parameter

This adds a new paramter to reset/update existing blacklisted nodes
set prior to this update with either node delete or using parameter
{{role.name}}RemovalPolicies.

Related-Bug: #1741053
Change-Id: I870d7605e35a7cda76d9de0e8830a87c898533d6
(cherry picked from commit b3b9b44dae)

overcloud.j2.yaml

@@ -197,6 +197,15 @@ parameters:
       doing an update which requires removal of specific resources.
       Example format ComputeRemovalPolicies: [{'resource_list': ['0']}]
 
+  {{role.name}}RemovalPoliciesMode:
+    default: append
+    type: string
+    description: >
+      How to handle change to RemovalPolicies for {{role.name}}
+      ResourceGroup when doing an update. Default mode 'append' will
+      append to the existing blacklist and 'update' would replace
+      the blacklist.
+
   {{role.name}}SchedulerHints:
     type: json
     description: Optional scheduler hints to pass to nova
@@ -556,6 +565,7 @@ resources:
     properties:
       count: {get_param: {{role.name}}Count}
       removal_policies: {get_param: {{role.name}}RemovalPolicies}
+      removal_policies_mode: {get_param: {{role.name}}RemovalPoliciesMode}
       resource_def:
         type: OS::TripleO::{{role.name}}
         properties:

releasenotes/notes/add-removal-policies-mode-6869362fbeed2cd2.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    The parameter {{role.name}}RemovalPoliciesMode can be set to 'update' to
+    reset the existing blacklisted nodes in heat. This will help re-use the
+    node indexes when required.