diff --git a/releasenotes/notes/drop-DEFAULT_PARAMS-bfcc2e7b74ef880b.yaml b/releasenotes/notes/drop-DEFAULT_PARAMS-bfcc2e7b74ef880b.yaml
new file mode 100644
index 0000000..c9a49a7
--- /dev/null
+++ b/releasenotes/notes/drop-DEFAULT_PARAMS-bfcc2e7b74ef880b.yaml
@@ -0,0 +1,13 @@
+---
+upgrade:
+  - |
+    Replace any call in your code to credentials_factory.DEFAULT_PARAMS with
+    a call to config.service_client_config().
+fixes:
+  - |
+    The credentials_factory module used to load configuration at import time
+    which caused configuration being loaded at test discovery time.
+    This was fixed by removing the DEFAULT_PARAMS variable. This variable
+    was redundant (and outdated), the same dictionary (but up to date) can
+    be obtained via invoking config.service_client_config() with no service
+    parameter.
diff --git a/tempest/api/network/test_routers.py b/tempest/api/network/test_routers.py
index 99ffaa8..abbb779 100644
--- a/tempest/api/network/test_routers.py
+++ b/tempest/api/network/test_routers.py
@@ -65,9 +65,12 @@
                           'The public_network_id option must be specified.')
     def test_create_show_list_update_delete_router(self):
         # Create a router
+        name = data_utils.rand_name(self.__class__.__name__ + '-router')
         router = self._create_router(
+            name=name,
             admin_state_up=False,
             external_network_id=CONF.network.public_network_id)
+        self.assertEqual(router['name'], name)
         self.assertEqual(router['admin_state_up'], False)
         self.assertEqual(
             router['external_gateway_info']['network_id'],
diff --git a/tempest/common/credentials_factory.py b/tempest/common/credentials_factory.py
index a340531..da34975 100644
--- a/tempest/common/credentials_factory.py
+++ b/tempest/common/credentials_factory.py
@@ -219,13 +219,6 @@
     'alt_user': ('identity', 'alt')
 }
 
-DEFAULT_PARAMS = {
-    'disable_ssl_certificate_validation':
-        CONF.identity.disable_ssl_certificate_validation,
-    'ca_certs': CONF.identity.ca_certificates_file,
-    'trace_requests': CONF.debug.trace_requests
-}
-
 
 def get_configured_admin_credentials(fill_in=True, identity_version=None):
     """Get admin credentials from the config file
@@ -252,7 +245,7 @@
     if identity_version == 'v3':
         conf_attributes.append('domain_name')
     # Read the parts of credentials from config
-    params = DEFAULT_PARAMS.copy()
+    params = config.service_client_config()
     for attr in conf_attributes:
         params[attr] = getattr(CONF.auth, 'admin_' + attr)
     # Build and validate credentials. We are reading configured credentials,
@@ -282,7 +275,7 @@
     :param kwargs: Attributes to be used to build the Credentials object.
     :returns: An object of a sub-type of `auth.Credentials`
     """
-    params = dict(DEFAULT_PARAMS, **kwargs)
+    params = dict(config.service_client_config(), **kwargs)
     identity_version = identity_version or CONF.identity.auth_version
     # In case of "v3" add the domain from config if not specified
     # To honour the "default_credentials_domain_name", if not domain
diff --git a/tempest/scenario/manager.py b/tempest/scenario/manager.py
index c34eddb..6a12b59 100644
--- a/tempest/scenario/manager.py
+++ b/tempest/scenario/manager.py
@@ -706,17 +706,14 @@
                         network['id'])
         return network
 
-    def _create_subnet(self, network, subnets_client=None,
-                       routers_client=None, namestart='subnet-smoke',
-                       **kwargs):
+    def create_subnet(self, network, subnets_client=None,
+                      namestart='subnet-smoke', **kwargs):
         """Create a subnet for the given network
 
         within the cidr block configured for tenant networks.
         """
         if not subnets_client:
             subnets_client = self.subnets_client
-        if not routers_client:
-            routers_client = self.routers_client
 
         def cidr_in_use(cidr, tenant_id):
             """Check cidr existence
@@ -1087,31 +1084,18 @@
             body = client.show_router(router_id)
             return body['router']
         elif network_id:
-            router = self._create_router(client, tenant_id)
-            kwargs = {'external_gateway_info': dict(network_id=network_id)}
-            router = client.update_router(router['id'], **kwargs)['router']
+            router = client.create_router(
+                name=data_utils.rand_name(self.__class__.__name__ + '-router'),
+                admin_state_up=True,
+                tenant_id=tenant_id,
+                external_gateway_info=dict(network_id=network_id))['router']
+            self.addCleanup(test_utils.call_and_ignore_notfound_exc,
+                            client.delete_router, router['id'])
             return router
         else:
             raise Exception("Neither of 'public_router_id' or "
                             "'public_network_id' has been defined.")
 
-    def _create_router(self, client=None, tenant_id=None,
-                       namestart='router-smoke'):
-        if not client:
-            client = self.routers_client
-        if not tenant_id:
-            tenant_id = client.tenant_id
-        name = data_utils.rand_name(namestart)
-        result = client.create_router(name=name,
-                                      admin_state_up=True,
-                                      tenant_id=tenant_id)
-        router = result['router']
-        self.assertEqual(router['name'], name)
-        self.addCleanup(test_utils.call_and_ignore_notfound_exc,
-                        client.delete_router,
-                        router['id'])
-        return router
-
     def create_networks(self, networks_client=None,
                         routers_client=None, subnets_client=None,
                         tenant_id=None, dns_nameservers=None,
@@ -1146,12 +1130,11 @@
             router = self._get_router(client=routers_client,
                                       tenant_id=tenant_id)
             subnet_kwargs = dict(network=network,
-                                 subnets_client=subnets_client,
-                                 routers_client=routers_client)
+                                 subnets_client=subnets_client)
             # use explicit check because empty list is a valid option
             if dns_nameservers is not None:
                 subnet_kwargs['dns_nameservers'] = dns_nameservers
-            subnet = self._create_subnet(**subnet_kwargs)
+            subnet = self.create_subnet(**subnet_kwargs)
             if not routers_client:
                 routers_client = self.routers_client
             router_id = router['id']
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index 8937104..6332c6d 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -227,10 +227,10 @@
     def _create_new_network(self, create_gateway=False):
         self.new_net = self._create_network()
         if create_gateway:
-            self.new_subnet = self._create_subnet(
+            self.new_subnet = self.create_subnet(
                 network=self.new_net)
         else:
-            self.new_subnet = self._create_subnet(
+            self.new_subnet = self.create_subnet(
                 network=self.new_net,
                 gateway_ip=None)
 
diff --git a/tempest/scenario/test_network_v6.py b/tempest/scenario/test_network_v6.py
index b687aa0..210f0ba 100644
--- a/tempest/scenario/test_network_v6.py
+++ b/tempest/scenario/test_network_v6.py
@@ -78,9 +78,9 @@
         if dualnet:
             network_v6 = self._create_network()
 
-        sub4 = self._create_subnet(network=network,
-                                   namestart='sub4',
-                                   ip_version=4)
+        sub4 = self.create_subnet(network=network,
+                                  namestart='sub4',
+                                  ip_version=4)
 
         router = self._get_router()
         self.routers_client.add_router_interface(router['id'],
@@ -93,11 +93,11 @@
         self.subnets_v6 = []
         for _ in range(n_subnets6):
             net6 = network_v6 if dualnet else network
-            sub6 = self._create_subnet(network=net6,
-                                       namestart='sub6',
-                                       ip_version=6,
-                                       ipv6_ra_mode=address6_mode,
-                                       ipv6_address_mode=address6_mode)
+            sub6 = self.create_subnet(network=net6,
+                                      namestart='sub6',
+                                      ip_version=6,
+                                      ipv6_ra_mode=address6_mode,
+                                      ipv6_address_mode=address6_mode)
 
             self.routers_client.add_router_interface(router['id'],
                                                      subnet_id=sub6['id'])
diff --git a/tempest/tests/cmd/test_account_generator.py b/tempest/tests/cmd/test_account_generator.py
index f907bd0..8bf4c5b 100644
--- a/tempest/tests/cmd/test_account_generator.py
+++ b/tempest/tests/cmd/test_account_generator.py
@@ -44,6 +44,7 @@
         self.patchobject(config, 'TempestConfigPrivate',
                          fake_config.FakePrivate)
         self.opts = FakeOpts(version=identity_version)
+        self.patch('oslo_log.log.setup', autospec=True)
 
     def mock_resource_creation(self):
         fake_resource = dict(id='id', name='name')
diff --git a/tempest/tests/common/test_credentials_factory.py b/tempest/tests/common/test_credentials_factory.py
index 020818e..7cf87f8 100644
--- a/tempest/tests/common/test_credentials_factory.py
+++ b/tempest/tests/common/test_credentials_factory.py
@@ -183,7 +183,7 @@
         # Build the expected params
         expected_params = dict(
             [(field, value) for _, field, value in all_params])
-        expected_params.update(cf.DEFAULT_PARAMS)
+        expected_params.update(config.service_client_config())
         admin_creds = cf.get_configured_admin_credentials()
         mock_get_credentials.assert_called_once_with(
             fill_in=True, identity_version='v3', **expected_params)
@@ -205,7 +205,7 @@
         # Build the expected params
         expected_params = dict(
             [(field, value) for _, field, value in all_params])
-        expected_params.update(cf.DEFAULT_PARAMS)
+        expected_params.update(config.service_client_config())
         admin_creds = cf.get_configured_admin_credentials(
             fill_in=False, identity_version='v3')
         mock_get_credentials.assert_called_once_with(
@@ -232,7 +232,7 @@
         cfg.CONF.set_default('uri', expected_uri, 'identity')
         params = {'foo': 'bar'}
         expected_params = params.copy()
-        expected_params.update(cf.DEFAULT_PARAMS)
+        expected_params.update(config.service_client_config())
         result = cf.get_credentials(identity_version='v2', **params)
         self.assertEqual(expected_result, result)
         mock_auth_get_credentials.assert_called_once_with(
@@ -251,7 +251,7 @@
         params = {'foo': 'bar'}
         expected_params = params.copy()
         expected_params['domain_name'] = expected_domain
-        expected_params.update(cf.DEFAULT_PARAMS)
+        expected_params.update(config.service_client_config())
         result = cf.get_credentials(fill_in=False, identity_version='v3',
                                     **params)
         self.assertEqual(expected_result, result)
@@ -270,7 +270,7 @@
                              expected_domain, 'auth')
         params = {'foo': 'bar', 'user_domain_name': expected_domain}
         expected_params = params.copy()
-        expected_params.update(cf.DEFAULT_PARAMS)
+        expected_params.update(config.service_client_config())
         result = cf.get_credentials(fill_in=False, identity_version='v3',
                                     **params)
         self.assertEqual(expected_result, result)
diff --git a/tempest/tests/test_base_test.py b/tempest/tests/test_base_test.py
index 3ece11d..011bc9b 100644
--- a/tempest/tests/test_base_test.py
+++ b/tempest/tests/test_base_test.py
@@ -17,6 +17,7 @@
 
 from tempest import clients
 from tempest.common import credentials_factory as credentials
+from tempest import config
 from tempest.lib.common import fixed_network
 from tempest import test
 from tempest.tests import base
@@ -27,6 +28,8 @@
     def setUp(self):
         super(TestBaseTestCase, self).setUp()
         self.useFixture(fake_config.ConfigFixture())
+        self.patchobject(config, 'TempestConfigPrivate',
+                         fake_config.FakePrivate)
         self.fixed_network_name = 'fixed-net'
         cfg.CONF.set_default('fixed_network_name', self.fixed_network_name,
                              'compute')