diff --git a/.zuul.yaml b/.zuul.yaml
index 2bec8c4..9753656 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -294,6 +294,13 @@
         CINDER_ENABLED_BACKENDS: lvm:lvmdriver-1,lvm:lvmdriver-2
         ENABLE_VOLUME_MULTIATTACH: true
       tempest_concurrency: 2
+    group-vars:
+      # NOTE(mriedem): The ENABLE_VOLUME_MULTIATTACH variable is used on both
+      # the controller and subnode prior to Rocky so we have to make sure the
+      # variable is set in both locations.
+      subnode:
+        devstack_localrc:
+          ENABLE_VOLUME_MULTIATTACH: true
 
 - job:
     name: tempest-slow-py3
diff --git a/doc/source/test_removal.rst b/doc/source/test_removal.rst
index e249bdd..ff4fa09 100644
--- a/doc/source/test_removal.rst
+++ b/doc/source/test_removal.rst
@@ -128,8 +128,9 @@
 people to respond to removal proposals please add things to the agenda by the
 Monday before the meeting.
 
-The other option is to raise the removal on the openstack-dev mailing list.
-(for example see: http://lists.openstack.org/pipermail/openstack-dev/2016-February/086218.html )
+The other option is to raise the removal on the openstack-discuss mailing list.
+(for example see: http://lists.openstack.org/pipermail/openstack-dev/2016-February/086218.html
+or http://lists.openstack.org/pipermail/openstack-discuss/2019-March/003574.html )
 This will raise the issue to the wider community and attract at least the same
 (most likely more) attention than discussing it during the irc meeting. The
 only downside is that it might take more time to get a response, given the
diff --git a/tempest/api/compute/servers/test_device_tagging.py b/tempest/api/compute/servers/test_device_tagging.py
index d40f937..e817587 100644
--- a/tempest/api/compute/servers/test_device_tagging.py
+++ b/tempest/api/compute/servers/test_device_tagging.py
@@ -12,9 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import json
-
 from oslo_log import log as logging
+from oslo_serialization import jsonutils as json
 
 from tempest.api.compute import base
 from tempest.common import utils
diff --git a/tempest/api/network/admin/test_l3_agent_scheduler.py b/tempest/api/network/admin/test_l3_agent_scheduler.py
deleted file mode 100644
index 033bf55..0000000
--- a/tempest/api/network/admin/test_l3_agent_scheduler.py
+++ /dev/null
@@ -1,83 +0,0 @@
-# Copyright 2013 IBM Corp.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-from tempest.api.network import base
-from tempest.common import utils
-from tempest.lib import decorators
-from tempest.lib import exceptions
-
-AGENT_TYPE = 'L3 agent'
-AGENT_MODES = (
-    'legacy',
-    'dvr_snat'
-)
-
-
-class L3AgentSchedulerTestJSON(base.BaseAdminNetworkTest):
-    """Tests the following operations in the Neutron API:
-
-        List routers that the given L3 agent is hosting.
-        List L3 agents hosting the given router.
-        Add and Remove Router to L3 agent
-
-    v2.0 of the Neutron API is assumed.
-
-    The l3_agent_scheduler extension is required for these tests.
-    """
-
-    @classmethod
-    def skip_checks(cls):
-        super(L3AgentSchedulerTestJSON, cls).skip_checks()
-        if not utils.is_extension_enabled('l3_agent_scheduler', 'network'):
-            msg = "L3 Agent Scheduler Extension not enabled."
-            raise cls.skipException(msg)
-
-    @classmethod
-    def resource_setup(cls):
-        super(L3AgentSchedulerTestJSON, cls).resource_setup()
-        agents = cls.admin_agents_client.list_agents(
-            agent_type=AGENT_TYPE)['agents']
-        for agent in agents:
-            if (agent['configurations']['agent_mode'] in AGENT_MODES and
-                agent['alive']):
-                cls.agent = agent
-                break
-        else:
-            msg = "L3 Agent Scheduler enabled in conf, but L3 Agent not found"
-            raise exceptions.InvalidConfiguration(msg)
-        cls.router = cls.create_router()
-
-    @decorators.idempotent_id('b7ce6e89-e837-4ded-9b78-9ed3c9c6a45a')
-    def test_list_routers_on_l3_agent(self):
-        self.admin_agents_client.list_routers_on_l3_agent(self.agent['id'])
-
-    @decorators.idempotent_id('9464e5e7-8625-49c3-8fd1-89c52be59d66')
-    def test_add_list_remove_router_on_l3_agent(self):
-        l3_agent_ids = list()
-        self.admin_agents_client.create_router_on_l3_agent(
-            self.agent['id'],
-            router_id=self.router['id'])
-        body = (
-            self.admin_routers_client.list_l3_agents_hosting_router(
-                self.router['id']))
-        for agent in body['agents']:
-            l3_agent_ids.append(agent['id'])
-            self.assertIn('agent_type', agent)
-            self.assertEqual('L3 agent', agent['agent_type'])
-        self.assertIn(self.agent['id'], l3_agent_ids)
-        body = self.admin_agents_client.delete_router_from_l3_agent(
-            self.agent['id'],
-            self.router['id'])
-        # NOTE(afazekas): The deletion not asserted, because neutron
-        # is not forbidden to reschedule the router to the same agent
diff --git a/tempest/cmd/run.py b/tempest/cmd/run.py
index cd1d26e..bb3fe63 100644
--- a/tempest/cmd/run.py
+++ b/tempest/cmd/run.py
@@ -252,7 +252,7 @@
                             default=False)
         # execution args
         parser.add_argument('--concurrency', '-w',
-                            type=int,
+                            type=int, default=0,
                             help="The number of workers to use, defaults to "
                                  "the number of cpus")
         parallel = parser.add_mutually_exclusive_group()
diff --git a/tempest/cmd/subunit_describe_calls.py b/tempest/cmd/subunit_describe_calls.py
index 8dcf575..081fa7a 100644
--- a/tempest/cmd/subunit_describe_calls.py
+++ b/tempest/cmd/subunit_describe_calls.py
@@ -78,11 +78,11 @@
 import argparse
 import collections
 import io
-import json
 import os
 import re
 import sys
 
+from oslo_serialization import jsonutils as json
 import subunit
 import testtools
 
diff --git a/tempest/lib/common/utils/misc.py b/tempest/lib/common/utils/misc.py
index 2b0fcd5..a0b0c0a 100644
--- a/tempest/lib/common/utils/misc.py
+++ b/tempest/lib/common/utils/misc.py
@@ -12,9 +12,6 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-from oslo_log import log as logging
-
-LOG = logging.getLogger(__name__)
 
 
 def singleton(cls):
diff --git a/tempest/lib/decorators.py b/tempest/lib/decorators.py
index 62a5d67..4064401 100644
--- a/tempest/lib/decorators.py
+++ b/tempest/lib/decorators.py
@@ -146,7 +146,7 @@
         # Check to see if the attr should be conditional applied.
         if 'condition' in kwargs and not kwargs.get('condition'):
             return f
-        if 'type' in kwargs and isinstance(kwargs['type'], str):
+        if 'type' in kwargs and isinstance(kwargs['type'], six.string_types):
             f = testtools.testcase.attr(kwargs['type'])(f)
         elif 'type' in kwargs and isinstance(kwargs['type'], list):
             for attr in kwargs['type']:
diff --git a/tempest/scenario/test_server_basic_ops.py b/tempest/scenario/test_server_basic_ops.py
index 1671216..02bc692 100644
--- a/tempest/scenario/test_server_basic_ops.py
+++ b/tempest/scenario/test_server_basic_ops.py
@@ -13,7 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import json
+from oslo_serialization import jsonutils as json
 
 from tempest.common import utils
 from tempest.common import waiters
diff --git a/tempest/scenario/test_volume_boot_pattern.py b/tempest/scenario/test_volume_boot_pattern.py
index e255329..6ed7e30 100644
--- a/tempest/scenario/test_volume_boot_pattern.py
+++ b/tempest/scenario/test_volume_boot_pattern.py
@@ -11,7 +11,7 @@
 #    under the License.
 
 from oslo_log import log as logging
-from oslo_serialization import jsonutils
+from oslo_serialization import jsonutils as json
 import testtools
 
 from tempest.common import utils
@@ -264,7 +264,7 @@
         bdms = image.get('block_device_mapping')
         if not bdms:
             bdms = image['properties']['block_device_mapping']
-        bdms = jsonutils.loads(bdms)
+        bdms = json.loads(bdms)
         snapshot_id = bdms[0]['snapshot_id']
         self._delete_snapshot(snapshot_id)
 
diff --git a/tempest/tests/lib/common/test_rest_client.py b/tempest/tests/lib/common/test_rest_client.py
index 4c0bb57..b861582 100644
--- a/tempest/tests/lib/common/test_rest_client.py
+++ b/tempest/tests/lib/common/test_rest_client.py
@@ -13,10 +13,10 @@
 #    under the License.
 
 import copy
-import json
 
 import fixtures
 import jsonschema
+from oslo_serialization import jsonutils as json
 import six
 
 from tempest.lib.common import http
diff --git a/tempest/tests/lib/services/identity/v2/test_token_client.py b/tempest/tests/lib/services/identity/v2/test_token_client.py
index dfce9b3..a592ada 100644
--- a/tempest/tests/lib/services/identity/v2/test_token_client.py
+++ b/tempest/tests/lib/services/identity/v2/test_token_client.py
@@ -12,9 +12,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import json
-
 import mock
+from oslo_serialization import jsonutils as json
 
 from tempest.lib.common import rest_client
 from tempest.lib import exceptions
diff --git a/tempest/tests/lib/services/identity/v3/test_token_client.py b/tempest/tests/lib/services/identity/v3/test_token_client.py
index 38e8c4a..a9c58df 100644
--- a/tempest/tests/lib/services/identity/v3/test_token_client.py
+++ b/tempest/tests/lib/services/identity/v3/test_token_client.py
@@ -12,9 +12,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import json
-
 import mock
+from oslo_serialization import jsonutils as json
 
 from tempest.lib.common import rest_client
 from tempest.lib import exceptions
diff --git a/tox.ini b/tox.ini
index 72f48a5..433f168 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = pep8,py36,py27,pip-check-reqs
+envlist = pep8,py36,py37,py27,pip-check-reqs
 minversion = 2.3.1
 skipsdist = True