Deprecate [designate] admin_* parameters

The admin_* parameters are implementing the same functionality as
keystoneauth parameters alghouth these don't provide all parameters for
Keystone v3 identity but are still based on Keystone v2 identity.
This change deprecates these parameters so that we can remove
such redundant and outdated definitions in a future release.

Closes-Bug: #1927494
Change-Id: I6294098008fbebb2e64922b3aaa085c1361d48a2

neutron/conf/services/extdns_designate_driver.py

@@ -22,19 +22,39 @@ designate_opts = [
     cfg.StrOpt('url',
                help=_('URL for connecting to designate')),
     cfg.StrOpt('admin_username',
+               deprecated_for_removal=True,
+               deprecated_since='Xena',
+               deprecated_reason=("This option will be completely replaced by "
+                                  "keystoneauth parameters."),
                help=_('Username for connecting to designate in admin '
                       'context')),
     cfg.StrOpt('admin_password',
+               deprecated_for_removal=True,
+               deprecated_since='Xena',
+               deprecated_reason=("This option will be completely replaced by "
+                                  "keystoneauth parameters."),
                help=_('Password for connecting to designate in admin '
                       'context'),
                secret=True),
     cfg.StrOpt('admin_tenant_id',
+               deprecated_for_removal=True,
+               deprecated_since='Xena',
+               deprecated_reason=("This option will be completely replaced by "
+                                  "keystoneauth parameters."),
                help=_('Tenant id for connecting to designate in admin '
                       'context')),
     cfg.StrOpt('admin_tenant_name',
+               deprecated_for_removal=True,
+               deprecated_since='Xena',
+               deprecated_reason=("This option will be completely replaced by "
+                                  "keystoneauth parameters."),
                help=_('Tenant name for connecting to designate in admin '
                       'context')),
     cfg.StrOpt('admin_auth_url',
+               deprecated_for_removal=True,
+               deprecated_since='Xena',
+               deprecated_reason=("This option will be completely replaced by "
+                                  "keystoneauth parameters."),
                help=_('Authorization URL for connecting to designate in admin '
                       'context')),
     cfg.BoolOpt('allow_reverse_dns_lookup', default=True,

neutron/services/externaldns/drivers/designate/driver.py

@@ -51,6 +51,7 @@ def get_clients(context):
         admin_auth = loading.load_auth_from_conf_options(
             CONF, 'designate')
     else:
+        # TODO(tkajinam): Make this fail when admin_* parameters are removed.
         admin_auth = password.Password(
             auth_url=CONF.designate.admin_auth_url,
             username=CONF.designate.admin_username,

releasenotes/notes/deprecate-designate-auth-opts-c2b1050a0360981c.yaml

@@ -0,0 +1,13 @@
+---
+deprecations:
+  - |
+    The following parameters in the ``designate`` section have been deprecated
+    and will be removed in a future release.
+    The ``[designate] auth_type`` parameter and required keystoneauth
+    parameters should be used instead.
+
+    - ``admin_username``
+    - ``admin_password``
+    - ``admin_tenant_id``
+    - ``admin_tenant_name``
+    - ``admin_auth_url``