diff --git a/nova/conf/quota.py b/nova/conf/quota.py
index 4766a8b286..d8dc1eb9d7 100644
--- a/nova/conf/quota.py
+++ b/nova/conf/quota.py
@@ -287,24 +287,21 @@ to help keep quota usage up-to-date and reduce the impact of out of sync usage
 issues. Note that quotas are not updated on a periodic task, they will update
 on a new reservation if max_age has passed since the last reservation.
 """),
-# TODO(pumaranikar): Add a new config to select between the db_driver and
-# the no_op driver using stevedore.
     cfg.StrOpt('driver',
-        default='nova.quota.DbQuotaDriver',
-        deprecated_for_removal=True,
-        deprecated_since='14.0.0',
-        deprecated_group='DEFAULT',
-        deprecated_name='quota_driver',
-        help="""
-The quota enforcer driver.
-
+               default='nova.quota.DbQuotaDriver',
+               choices=('nova.quota.DbQuotaDriver',
+                        'nova.quota.NoopQuotaDriver'),
+               help="""
 Provides abstraction for quota checks. Users can configure a specific
 driver to use for quota checks.
 
 Possible values:
 
-* nova.quota.DbQuotaDriver (default) or any string representing fully
-  qualified class name.
+* nova.quota.DbQuotaDriver: Stores quota limit information
+  in the database and relies on the quota_* configuration options for default
+  quota limit values. Counts quota usage on-demand.
+* nova.quota.NoopQuotaDriver: Ignores quota and treats all resources as
+  unlimited.
 """),
     cfg.BoolOpt('recheck_quota',
         default=True,
diff --git a/nova/quota.py b/nova/quota.py
index dde040e5c8..c8e4ad3168 100644
--- a/nova/quota.py
+++ b/nova/quota.py
@@ -20,7 +20,6 @@ import copy
 
 from oslo_log import log as logging
 from oslo_utils import importutils
-import six
 
 import nova.conf
 from nova import context as nova_context
@@ -995,21 +994,18 @@ class CountableResource(AbsoluteResource):
 class QuotaEngine(object):
     """Represent the set of recognized quotas."""
 
-    def __init__(self, quota_driver_class=None):
+    def __init__(self, quota_driver=None):
         """Initialize a Quota object."""
         self._resources = {}
-        self._driver_cls = quota_driver_class
-        self.__driver = None
+        # NOTE(mriedem): quota_driver is ever only supplied in tests with a
+        # fake driver.
+        self.__driver = quota_driver
 
     @property
     def _driver(self):
         if self.__driver:
             return self.__driver
-        if not self._driver_cls:
-            self._driver_cls = CONF.quota.driver
-        if isinstance(self._driver_cls, six.string_types):
-            self._driver_cls = importutils.import_object(self._driver_cls)
-        self.__driver = self._driver_cls
+        self.__driver = importutils.import_object(CONF.quota.driver)
         return self.__driver
 
     def register_resource(self, resource):
diff --git a/nova/tests/unit/compute/test_compute_cells.py b/nova/tests/unit/compute/test_compute_cells.py
index 68b93754f9..deb54a58ec 100644
--- a/nova/tests/unit/compute/test_compute_cells.py
+++ b/nova/tests/unit/compute/test_compute_cells.py
@@ -66,7 +66,7 @@ def stub_call_to_cells(context, instance, method, *args, **kwargs):
     # Use NoopQuotaDriver in child cells.
     saved_quotas = quota.QUOTAS
     quota.QUOTAS = quota.QuotaEngine(
-            quota_driver_class=quota.NoopQuotaDriver())
+            quota_driver=quota.NoopQuotaDriver())
     compute_api.QUOTAS = quota.QUOTAS
     try:
         return fn(context, instance, *args, **kwargs)
@@ -88,7 +88,7 @@ def stub_cast_to_cells(context, instance, method, *args, **kwargs):
     # Use NoopQuotaDriver in child cells.
     saved_quotas = quota.QUOTAS
     quota.QUOTAS = quota.QuotaEngine(
-            quota_driver_class=quota.NoopQuotaDriver())
+            quota_driver=quota.NoopQuotaDriver())
     compute_api.QUOTAS = quota.QUOTAS
     try:
         fn(context, instance, *args, **kwargs)
diff --git a/nova/tests/unit/test_quota.py b/nova/tests/unit/test_quota.py
index e3c0264441..bcb4b7cdbe 100644
--- a/nova/tests/unit/test_quota.py
+++ b/nova/tests/unit/test_quota.py
@@ -489,15 +489,8 @@ class QuotaEngineTestCase(test.TestCase):
         self.assertEqual(quota_obj._resources, {})
         self.assertIsInstance(quota_obj._driver, quota.DbQuotaDriver)
 
-    def test_init_override_string(self):
-        quota_obj = quota.QuotaEngine(
-            quota_driver_class='nova.tests.unit.test_quota.FakeDriver')
-
-        self.assertEqual(quota_obj._resources, {})
-        self.assertIsInstance(quota_obj._driver, FakeDriver)
-
     def test_init_override_obj(self):
-        quota_obj = quota.QuotaEngine(quota_driver_class=FakeDriver)
+        quota_obj = quota.QuotaEngine(quota_driver=FakeDriver)
 
         self.assertEqual(quota_obj._resources, {})
         self.assertEqual(quota_obj._driver, FakeDriver)
@@ -528,7 +521,7 @@ class QuotaEngineTestCase(test.TestCase):
         context = FakeContext('test_project', 'test_class')
         driver = FakeDriver(by_user=dict(
                 fake_user=dict(test_resource=42)))
-        quota_obj = quota.QuotaEngine(quota_driver_class=driver)
+        quota_obj = quota.QuotaEngine(quota_driver=driver)
         result = quota_obj.get_by_project_and_user(context, 'test_project',
                                        'fake_user', 'test_resource')
 
@@ -542,7 +535,7 @@ class QuotaEngineTestCase(test.TestCase):
         context = FakeContext('test_project', 'test_class')
         driver = FakeDriver(by_project=dict(
                 test_project=dict(test_resource=42)))
-        quota_obj = quota.QuotaEngine(quota_driver_class=driver)
+        quota_obj = quota.QuotaEngine(quota_driver=driver)
         result = quota_obj.get_by_project(context, 'test_project',
                                           'test_resource')
 
@@ -555,7 +548,7 @@ class QuotaEngineTestCase(test.TestCase):
         context = FakeContext('test_project', 'test_class')
         driver = FakeDriver(by_class=dict(
                 test_class=dict(test_resource=42)))
-        quota_obj = quota.QuotaEngine(quota_driver_class=driver)
+        quota_obj = quota.QuotaEngine(quota_driver=driver)
         result = quota_obj.get_by_class(context, 'test_class', 'test_resource')
 
         self.assertEqual(driver.called, [
@@ -564,7 +557,7 @@ class QuotaEngineTestCase(test.TestCase):
         self.assertEqual(result, 42)
 
     def _make_quota_obj(self, driver):
-        quota_obj = quota.QuotaEngine(quota_driver_class=driver)
+        quota_obj = quota.QuotaEngine(quota_driver=driver)
         resources = [
             quota.AbsoluteResource('test_resource4'),
             quota.AbsoluteResource('test_resource3'),
diff --git a/releasenotes/notes/rocky-quota-driver-config-6459e19ef2b43aa2.yaml b/releasenotes/notes/rocky-quota-driver-config-6459e19ef2b43aa2.yaml
new file mode 100644
index 0000000000..5c630e3bba
--- /dev/null
+++ b/releasenotes/notes/rocky-quota-driver-config-6459e19ef2b43aa2.yaml
@@ -0,0 +1,11 @@
+---
+upgrade:
+  - |
+    The ``[quota]/driver`` configuration option is no longer deprecated
+    but now only allows one of two possible values:
+
+    * ``nova.quota.DbQuotaDriver``
+    * ``nova.quota.NoopQuotaDriver``
+
+    This means it is no longer possible to class-load custom out-of-tree
+    quota drivers.
\ No newline at end of file