Modify RGW client format

With changes to config_template module that restored usage of {% raw %} tags [1]
renderring of mapping keys, if they're defined as variables, was broken.

Ansible, by design [2], does not render mapping keys. Moreover, it was not
working as intended anyway, since renderring happened in post-copy stage
so same records were not merged together, which resulted in #1812245

As such behaviour is expected by Ansible design, instead of adding some
workaround in config_template module, I suggest working around issue
by defining troublesome mapping with Jinja, that will allow it to render properly.

[1] https://review.opendev.org/c/openstack/ansible-config_template/+/881887
[2] https://github.com/ansible/ansible/issues/17324#issuecomment-685102595

Closes-Bug: #2048036
Related-Bug: #1812245
Change-Id: I8a32736239c6326d817c620451799c13d5d8938c

inventory/group_vars/ceph-rgw.yml

@@ -1,19 +1,23 @@
 ---
-ceph_conf_overrides_rgw:
-  "client.rgw.{{ hostvars[inventory_hostname]['ansible_facts']['hostname'] }}.rgw0":
-    # OpenStack integration with Keystone
-    rgw_keystone_url: "{{ keystone_service_adminuri }}"
-    rgw_keystone_api_version: 3
-    rgw_keystone_admin_user: "{{ radosgw_admin_user }}"
-    rgw_keystone_admin_password: "{{ radosgw_admin_password }}"
-    rgw_keystone_admin_project: "{{ radosgw_admin_tenant }}"
-    rgw_keystone_admin_domain: default
-    rgw_keystone_accepted_roles: 'member, admin, swiftoperator'
-    rgw_keystone_implicit_tenants: 'true'
-    rgw_swift_account_in_url: 'true'
-    rgw_swift_versioning_enabled: 'true'
-    rgw_enable_apis: 'swift, s3'
-    rgw_s3_auth_use_keystone: 'true'
+ceph_conf_overrides_rgw: |-
+  {{
+    {
+      'client.rgw.' ~ hostvars[inventory_hostname]['ansible_facts']['hostname'] ~ '.rgw0': {
+        'rgw_keystone_url': keystone_service_adminuri,
+        'rgw_keystone_api_version': 3,
+        'rgw_keystone_admin_user': radosgw_admin_user,
+        'rgw_keystone_admin_password': radosgw_admin_password,
+        'rgw_keystone_admin_project': radosgw_admin_tenant,
+        'rgw_keystone_admin_domain': 'default',
+        'rgw_keystone_accepted_roles': 'member, admin, swiftoperator',
+        'rgw_keystone_implicit_tenants': 'true',
+        'rgw_swift_account_in_url': 'true',
+        'rgw_swift_versioning_enabled': 'true',
+        'rgw_enable_apis': 'swift, s3',
+        'rgw_s3_auth_use_keystone': 'true'
+      }
+    }
+  }}
 
 ###
 ### Backend TLS

releasenotes/notes/config_overrides_dict_key_vars-962b4bebca02c477.yaml

@@ -0,0 +1,34 @@
+---
+
+issues:
+  - |
+    With recent changes to config_template module, it is not possible
+    anymore to have variables as dictionary keys in overrides. Example below
+    will not be renderred properly:
+
+    .. code-block:: yaml
+
+      config_overrides:
+        "{{ inventory_hostname }}":
+          cruel: world
+
+    This limitation boils down to Ansible design and will be true for any other
+    module as well.
+    In order to overcome it, you can transform the dictionary to a Jinja2 format:
+
+    .. code-block:: yaml
+
+      config_overrides: |-
+        {{
+          {
+            inventory_hostname: {
+              'cruel': 'world'
+            }
+          }
+        }}
+
+fixes:
+  - |
+    Fixes format of ``ceph_conf_overrides_rgw`` variable by converting override
+    dictionary to Jinja2 format to workaround Ansible limitation on usage of
+    variables as keys in dictionary.