diff --git a/releasenotes/notes/add-tempest-run-combine-option-e94c1049ba8985d5.yaml b/releasenotes/notes/add-tempest-run-combine-option-e94c1049ba8985d5.yaml
new file mode 100644
index 0000000..73900ca
--- /dev/null
+++ b/releasenotes/notes/add-tempest-run-combine-option-e94c1049ba8985d5.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Adds a new cli option to tempest run, --combine, which is used to indicate
+    you want the subunit stream output combined with the previous run's in
+    the testr repository
diff --git a/tempest/api/compute/test_versions.py b/tempest/api/compute/test_versions.py
index c9f0724..dcab067 100644
--- a/tempest/api/compute/test_versions.py
+++ b/tempest/api/compute/test_versions.py
@@ -14,11 +14,13 @@
 
 from tempest.api.compute import base
 from tempest.lib import decorators
+from tempest import test
 
 
 class TestVersions(base.BaseV2ComputeTest):
 
     @decorators.idempotent_id('6c0a0990-43b6-4529-9b61-5fd8daf7c55c')
+    @test.attr(type='smoke')
     def test_list_api_versions(self):
         """Test that a get of the unversioned url returns the choices doc.
 
@@ -37,6 +39,7 @@
                          "The first listed version should be v2.0")
 
     @decorators.idempotent_id('b953a29e-929c-4a8e-81be-ec3a7e03cb76')
+    @test.attr(type='smoke')
     def test_get_version_details(self):
         """Test individual version endpoints info works.
 
diff --git a/tempest/cmd/run.py b/tempest/cmd/run.py
index 54b844a..b36bf5c 100644
--- a/tempest/cmd/run.py
+++ b/tempest/cmd/run.py
@@ -78,11 +78,20 @@
 subunit-trace output filter. But, if you would prefer a subunit v2 stream be
 output to STDOUT use the **--subunit** flag
 
+Combining Runs
+==============
+
+There are certain situations in which you want to split a single run of tempest
+across 2 executions of tempest run. (for example to run part of the tests
+serially and others in parallel) To accomplish this but still treat the results
+as a single run you can leverage the **--combine** option which will append
+the current run's results with the previous runs.
 """
 
 import io
 import os
 import sys
+import tempfile
 import threading
 
 from cliff import command
@@ -165,6 +174,12 @@
         else:
             print("No .testr.conf file was found for local execution")
             sys.exit(2)
+        if parsed_args.combine:
+            temp_stream = tempfile.NamedTemporaryFile()
+            return_code = run_argv(['tempest', 'last', '--subunit'], sys.stdin,
+                                   temp_stream, sys.stderr)
+            if return_code > 0:
+                sys.exit(return_code)
 
         regex = self._build_regex(parsed_args)
         if parsed_args.list_tests:
@@ -173,6 +188,16 @@
         else:
             options = self._build_options(parsed_args)
             returncode = self._run(regex, options)
+            if returncode > 0:
+                sys.exit(returncode)
+
+        if parsed_args.combine:
+            return_code = run_argv(['tempest', 'last', '--subunit'], sys.stdin,
+                                   temp_stream, sys.stderr)
+            if return_code > 0:
+                sys.exit(return_code)
+            returncode = run_argv(['tempest', 'load', temp_stream.name],
+                                  sys.stdin, sys.stdout, sys.stderr)
         sys.exit(returncode)
 
     def get_description(self):
@@ -231,6 +256,10 @@
         # output args
         parser.add_argument("--subunit", action='store_true',
                             help='Enable subunit v2 output')
+        parser.add_argument("--combine", action='store_true',
+                            help='Combine the output of this run with the '
+                                 "previous run's as a combined stream in the "
+                                 "testr repository after it finish")
 
         parser.set_defaults(parallel=True)
         return parser
diff --git a/tempest/scenario/test_aggregates_basic_ops.py b/tempest/scenario/test_aggregates_basic_ops.py
index 5152472..b0b516a 100644
--- a/tempest/scenario/test_aggregates_basic_ops.py
+++ b/tempest/scenario/test_aggregates_basic_ops.py
@@ -96,6 +96,7 @@
         return aggregate
 
     @decorators.idempotent_id('cb2b4c4f-0c7c-4164-bdde-6285b302a081')
+    @test.attr(type='slow')
     @test.services('compute')
     def test_aggregate_basic_ops(self):
         self.useFixture(fixtures.LockFixture('availability_zone'))
diff --git a/tempest/scenario/test_encrypted_cinder_volumes.py b/tempest/scenario/test_encrypted_cinder_volumes.py
index da29485..a05b1b1 100644
--- a/tempest/scenario/test_encrypted_cinder_volumes.py
+++ b/tempest/scenario/test_encrypted_cinder_volumes.py
@@ -62,6 +62,7 @@
         self.nova_volume_detach(server, attached_volume)
 
     @decorators.idempotent_id('79165fb4-5534-4b9d-8429-97ccffb8f86e')
+    @test.attr(type='slow')
     @test.services('compute', 'volume', 'image')
     def test_encrypted_cinder_volumes_luks(self):
         server = self.launch_instance()
@@ -71,6 +72,7 @@
         self.attach_detach_volume(server, volume)
 
     @decorators.idempotent_id('cbc752ed-b716-4717-910f-956cce965722')
+    @test.attr(type='slow')
     @test.services('compute', 'volume', 'image')
     def test_encrypted_cinder_volumes_cryptsetup(self):
         server = self.launch_instance()
diff --git a/tempest/scenario/test_network_advanced_server_ops.py b/tempest/scenario/test_network_advanced_server_ops.py
index 1196659..6665fa7 100644
--- a/tempest/scenario/test_network_advanced_server_ops.py
+++ b/tempest/scenario/test_network_advanced_server_ops.py
@@ -104,6 +104,7 @@
         return body['OS-EXT-SRV-ATTR:host']
 
     @decorators.idempotent_id('61f1aa9a-1573-410e-9054-afa557cab021')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_stop_start(self):
         keypair = self.create_keypair()
@@ -129,6 +130,7 @@
             server, keypair, floating_ip)
 
     @decorators.idempotent_id('88a529c2-1daa-4c85-9aec-d541ba3eb699')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_rebuild(self):
         keypair = self.create_keypair()
@@ -143,6 +145,7 @@
     @decorators.idempotent_id('2b2642db-6568-4b35-b812-eceed3fa20ce')
     @testtools.skipUnless(CONF.compute_feature_enabled.pause,
                           'Pause is not available.')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_pause_unpause(self):
         keypair = self.create_keypair()
@@ -160,6 +163,7 @@
     @decorators.idempotent_id('5cdf9499-541d-4923-804e-b9a60620a7f0')
     @testtools.skipUnless(CONF.compute_feature_enabled.suspend,
                           'Suspend is not available.')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_suspend_resume(self):
         keypair = self.create_keypair()
@@ -177,6 +181,7 @@
     @decorators.idempotent_id('719eb59d-2f42-4b66-b8b1-bb1254473967')
     @testtools.skipUnless(CONF.compute_feature_enabled.resize,
                           'Resize is not available.')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_resize(self):
         resize_flavor = CONF.compute.flavor_ref_alt
@@ -200,6 +205,7 @@
     @testtools.skipUnless(CONF.compute.min_compute_nodes > 1,
                           'Less than 2 compute nodes, skipping multinode '
                           'tests.')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_cold_migration(self):
         keypair = self.create_keypair()
@@ -225,6 +231,7 @@
     @testtools.skipUnless(CONF.compute.min_compute_nodes > 1,
                           'Less than 2 compute nodes, skipping multinode '
                           'tests.')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_server_connectivity_cold_migration_revert(self):
         keypair = self.create_keypair()
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index 51b59c9..e6a2e9d 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -406,6 +406,7 @@
     @decorators.idempotent_id('b158ea55-472e-4086-8fa9-c64ac0c6c1d0')
     @testtools.skipUnless(test.is_extension_enabled('net-mtu', 'network'),
                           'No way to calculate MTU for networks')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_mtu_sized_frames(self):
         """Validate that network MTU sized frames fit through."""
@@ -418,6 +419,7 @@
                       'Connectivity can only be tested when in a '
                       'multitenant network environment')
     @decorators.skip_because(bug="1610994")
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_connectivity_between_vms_on_different_networks(self):
         """Test connectivity between VMs on different networks
@@ -493,6 +495,7 @@
     @testtools.skipIf(CONF.network.shared_physical_network,
                       'Router state can be altered only with multitenant '
                       'networks capabilities')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_update_router_admin_state(self):
         """Test to update admin state up of router
@@ -526,6 +529,7 @@
                       'network isolation not available')
     @testtools.skipUnless(CONF.scenario.dhcp_client,
                           "DHCP client is not available.")
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_subnet_details(self):
         """Tests that subnet's extra configuration details are affecting VMs.
@@ -608,6 +612,7 @@
     @testtools.skipUnless(CONF.network_feature_enabled.port_admin_state_change,
                           "Changing a port's admin state is not supported "
                           "by the test environment")
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_update_instance_port_admin_state(self):
         """Test to update admin_state_up attribute of instance port
@@ -653,6 +658,7 @@
                                        should_succeed=True)
 
     @decorators.idempotent_id('759462e1-8535-46b0-ab3a-33aa45c55aaa')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_preserve_preexisting_port(self):
         """Test preserve pre-existing port
@@ -704,6 +710,7 @@
 
     @test.requires_ext(service='network', extension='l3_agent_scheduler')
     @decorators.idempotent_id('2e788c46-fb3f-4ac9-8f82-0561555bea73')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_router_rescheduling(self):
         """Tests that router can be removed from agent and add to a new agent.
@@ -783,6 +790,7 @@
     @testtools.skipUnless(CONF.compute_feature_enabled.interface_attach,
                           'NIC hotplug not available')
     @decorators.idempotent_id('7c0bb1a2-d053-49a4-98f9-ca1a1d849f63')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_port_security_macspoofing_port(self):
         """Tests port_security extension enforces mac spoofing
diff --git a/tempest/scenario/test_network_v6.py b/tempest/scenario/test_network_v6.py
index fcf395d..d8a1363 100644
--- a/tempest/scenario/test_network_v6.py
+++ b/tempest/scenario/test_network_v6.py
@@ -240,6 +240,7 @@
     def test_dualnet_dhcp6_stateless_from_os(self):
         self._prepare_and_test(address6_mode='dhcpv6-stateless', dualnet=True)
 
+    @test.attr(type='slow')
     @decorators.idempotent_id('cf1c4425-766b-45b8-be35-e2959728eb00')
     @test.services('compute', 'network')
     def test_dualnet_multi_prefix_dhcpv6_stateless(self):
diff --git a/tempest/scenario/test_object_storage_basic_ops.py b/tempest/scenario/test_object_storage_basic_ops.py
index c989e01..7fd8c91 100644
--- a/tempest/scenario/test_object_storage_basic_ops.py
+++ b/tempest/scenario/test_object_storage_basic_ops.py
@@ -46,6 +46,7 @@
         self.delete_container(container_name)
 
     @decorators.idempotent_id('916c7111-cb1f-44b2-816d-8f760e4ea910')
+    @test.attr(type='slow')
     @test.services('object_storage')
     def test_swift_acl_anonymous_download(self):
         """This test will cover below steps:
diff --git a/tempest/scenario/test_security_groups_basic_ops.py b/tempest/scenario/test_security_groups_basic_ops.py
index 3d383f7..fa12f33 100644
--- a/tempest/scenario/test_security_groups_basic_ops.py
+++ b/tempest/scenario/test_security_groups_basic_ops.py
@@ -494,6 +494,7 @@
             raise
 
     @decorators.idempotent_id('f4d556d7-1526-42ad-bafb-6bebf48568f6')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_port_update_new_security_group(self):
         """Verifies the traffic after updating the vm port
@@ -548,6 +549,7 @@
             raise
 
     @decorators.idempotent_id('d2f77418-fcc4-439d-b935-72eca704e293')
+    @test.attr(type='slow')
     @test.services('compute', 'network')
     def test_multiple_security_groups(self):
         """Verify multiple security groups and checks that rules
@@ -579,6 +581,7 @@
                                    private_key=private_key,
                                    should_connect=True)
 
+    @test.attr(type='slow')
     @test.requires_ext(service='network', extension='port-security')
     @decorators.idempotent_id('7c811dcc-263b-49a3-92d2-1b4d8405f50c')
     @test.services('compute', 'network')
@@ -619,6 +622,7 @@
                 self._log_console_output(servers=tenant.servers)
             raise
 
+    @test.attr(type='slow')
     @test.requires_ext(service='network', extension='port-security')
     @decorators.idempotent_id('13ccf253-e5ad-424b-9c4a-97b88a026699')
     @testtools.skipUnless(
diff --git a/tempest/scenario/test_server_advanced_ops.py b/tempest/scenario/test_server_advanced_ops.py
index ec839cd..1960e9a 100644
--- a/tempest/scenario/test_server_advanced_ops.py
+++ b/tempest/scenario/test_server_advanced_ops.py
@@ -48,6 +48,7 @@
         cls.set_network_resources()
         super(TestServerAdvancedOps, cls).setup_credentials()
 
+    @test.attr(type='slow')
     @decorators.idempotent_id('e6c28180-7454-4b59-b188-0257af08a63b')
     @testtools.skipUnless(CONF.compute_feature_enabled.resize,
                           'Resize is not available.')
@@ -69,6 +70,7 @@
         waiters.wait_for_server_status(self.servers_client, instance_id,
                                        'ACTIVE')
 
+    @test.attr(type='slow')
     @decorators.idempotent_id('949da7d5-72c8-4808-8802-e3d70df98e2c')
     @testtools.skipUnless(CONF.compute_feature_enabled.suspend,
                           'Suspend is not available.')
diff --git a/tempest/scenario/test_shelve_instance.py b/tempest/scenario/test_shelve_instance.py
index 75cef88..9e763f8 100644
--- a/tempest/scenario/test_shelve_instance.py
+++ b/tempest/scenario/test_shelve_instance.py
@@ -74,6 +74,7 @@
                                         private_key=keypair['private_key'])
         self.assertEqual(timestamp, timestamp2)
 
+    @test.attr(type='slow')
     @decorators.idempotent_id('1164e700-0af0-4a4c-8792-35909a88743c')
     @testtools.skipUnless(CONF.network.public_network_id,
                           'The public_network_id option must be specified.')
@@ -81,6 +82,7 @@
     def test_shelve_instance(self):
         self._create_server_then_shelve_and_unshelve()
 
+    @test.attr(type='slow')
     @decorators.idempotent_id('c1b6318c-b9da-490b-9c67-9339b627271f')
     @testtools.skipUnless(CONF.network.public_network_id,
                           'The public_network_id option must be specified.')
diff --git a/tempest/scenario/test_snapshot_pattern.py b/tempest/scenario/test_snapshot_pattern.py
index 6dedd1d..a699de2 100644
--- a/tempest/scenario/test_snapshot_pattern.py
+++ b/tempest/scenario/test_snapshot_pattern.py
@@ -41,6 +41,7 @@
             raise cls.skipException("Snapshotting is not available.")
 
     @decorators.idempotent_id('608e604b-1d63-4a82-8e3e-91bc665c90b4')
+    @test.attr(type='slow')
     @testtools.skipUnless(CONF.network.public_network_id,
                           'The public_network_id option must be specified.')
     @test.services('compute', 'network', 'image')
diff --git a/tempest/scenario/test_stamp_pattern.py b/tempest/scenario/test_stamp_pattern.py
index 716c0bf..aabb767 100644
--- a/tempest/scenario/test_stamp_pattern.py
+++ b/tempest/scenario/test_stamp_pattern.py
@@ -88,6 +88,7 @@
                                           CONF.compute.build_interval):
             raise lib_exc.TimeoutException
 
+    @test.attr(type='slow')
     @decorators.skip_because(bug="1664793")
     @decorators.idempotent_id('10fd234a-515c-41e5-b092-8323060598c5')
     @testtools.skipUnless(CONF.compute_feature_enabled.snapshot,
diff --git a/tempest/scenario/test_volume_boot_pattern.py b/tempest/scenario/test_volume_boot_pattern.py
index b72dae9..8cab19c 100644
--- a/tempest/scenario/test_volume_boot_pattern.py
+++ b/tempest/scenario/test_volume_boot_pattern.py
@@ -95,7 +95,6 @@
         waiters.wait_for_server_termination(self.servers_client, server['id'])
 
     @decorators.idempotent_id('557cd2c2-4eb8-4dce-98be-f86765ff311b')
-    @test.attr(type='smoke')
     @testtools.skipUnless(CONF.network.public_network_id,
                           'The public_network_id option must be specified.')
     @test.services('compute', 'volume', 'image')
@@ -177,6 +176,7 @@
         self.assertEqual(timestamp, timestamp3)
 
     @decorators.idempotent_id('05795fb2-b2a7-4c9f-8fac-ff25aedb1489')
+    @test.attr(type='slow')
     @test.services('compute', 'image', 'volume')
     def test_create_server_from_volume_snapshot(self):
         # Create a volume from an image
diff --git a/tempest/scenario/test_volume_migrate_attached.py b/tempest/scenario/test_volume_migrate_attached.py
index 891e22d..f580ea6 100644
--- a/tempest/scenario/test_volume_migrate_attached.py
+++ b/tempest/scenario/test_volume_migrate_attached.py
@@ -91,6 +91,7 @@
         waiters.wait_for_volume_retype(self.volumes_client,
                                        volume_id, new_volume_type)
 
+    @test.attr(type='slow')
     @decorators.idempotent_id('deadd2c2-beef-4dce-98be-f86765ff311b')
     @test.services('compute', 'volume')
     def test_volume_migrate_attached(self):
diff --git a/tools/tox_install.sh b/tools/tox_install.sh
new file mode 100755
index 0000000..43468e4
--- /dev/null
+++ b/tools/tox_install.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+# Client constraint file contains this client version pin that is in conflict
+# with installing the client from source. We should remove the version pin in
+# the constraints file before applying it for from-source installation.
+
+CONSTRAINTS_FILE=$1
+shift 1
+
+set -e
+
+# NOTE(tonyb): Place this in the tox enviroment's log dir so it will get
+# published to logs.openstack.org for easy debugging.
+localfile="$VIRTUAL_ENV/log/upper-constraints.txt"
+
+if [[ $CONSTRAINTS_FILE != http* ]]; then
+    CONSTRAINTS_FILE=file://$CONSTRAINTS_FILE
+fi
+# NOTE(tonyb): need to add curl to bindep.txt if the project supports bindep
+curl $CONSTRAINTS_FILE --insecure --progress-bar --output $localfile
+
+pip install -c$localfile openstack-requirements
+
+# This is the main purpose of the script: Allow local installation of
+# the current repo. It is listed in constraints file and thus any
+# install will be constrained and we need to unconstrain it.
+edit-constraints $localfile -- $CLIENT_NAME
+
+pip install -c$localfile -U $*
+exit $?
diff --git a/tox.ini b/tox.ini
index d8d390e..05331fa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,6 +8,8 @@
 setenv =
     VIRTUAL_ENV={envdir}
     OS_TEST_PATH=./tempest/test_discover
+    BRANCH_NAME=master
+    CLIENT_NAME=tempest
 deps =
     setuptools
     -r{toxinidir}/requirements.txt
@@ -17,9 +19,12 @@
     VIRTUAL_ENV={envdir}
     OS_TEST_PATH=./tempest/tests
     PYTHONWARNINGS=default::DeprecationWarning
-passenv = OS_STDOUT_CAPTURE OS_STDERR_CAPTURE OS_TEST_TIMEOUT OS_TEST_LOCK_PATH OS_TEST_PATH TEMPEST_CONFIG TEMPEST_CONFIG_DIR http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
+    BRANCH_NAME=master
+    CLIENT_NAME=tempest
+passenv = OS_STDOUT_CAPTURE OS_STDERR_CAPTURE OS_TEST_TIMEOUT OS_TEST_LOCK_PATH OS_TEST_PATH TEMPEST_CONFIG TEMPEST_CONFIG_DIR http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY ZUUL_CACHE_DIR REQUIREMENTS_PIP_LOCATION
 usedevelop = True
-install_command = pip install -U {opts} {packages}
+install_command =
+    {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 whitelist_externals = *
 deps =
     -r{toxinidir}/requirements.txt
@@ -78,7 +83,8 @@
 # See the testrepository bug: https://bugs.launchpad.net/testrepository/+bug/1208610
 commands =
     find . -type f -name "*.pyc" -delete
-    tempest run --regex '(?!.*\[.*\bslow\b.*\])(^tempest\.(api|scenario))' {posargs}
+    tempest run --regex '(?!.*\[.*\bslow\b.*\])(^tempest\.api)' {posargs}
+    tempest run --combine --serial --regex '(?!.*\[.*\bslow\b.*\])(^tempest\.scenario)' {posargs}
 
 [testenv:full-serial]
 envdir = .tox/tempest