diff --git a/tempest/scenario/manager.py b/tempest/scenario/manager.py
index 5d51d15..add4c37 100644
--- a/tempest/scenario/manager.py
+++ b/tempest/scenario/manager.py
@@ -91,10 +91,32 @@
             volume_microversion=self.volume_request_microversion,
             placement_microversion=self.placement_request_microversion))
 
+    def setup_compute_client(cls):
+        """Compute and Compute security groups client"""
+        cls.compute_images_client = cls.os_primary.compute_images_client
+        cls.keypairs_client = cls.os_primary.keypairs_client
+        cls.compute_security_groups_client = (
+            cls.os_primary.compute_security_groups_client)
+        cls.compute_security_group_rules_client = (
+            cls.os_primary.compute_security_group_rules_client)
+        cls.servers_client = cls.os_primary.servers_client
+        cls.interface_client = cls.os_primary.interfaces_client
+
+    def setup_network_client(cls):
+        """Neutron network client"""
+        cls.networks_client = cls.os_primary.networks_client
+        cls.ports_client = cls.os_primary.ports_client
+        cls.routers_client = cls.os_primary.routers_client
+        cls.subnets_client = cls.os_primary.subnets_client
+        cls.floating_ips_client = cls.os_primary.floating_ips_client
+        cls.security_groups_client = cls.os_primary.security_groups_client
+        cls.security_group_rules_client = (
+            cls.os_primary.security_group_rules_client)
+
     @classmethod
     def setup_clients(cls):
+        """This setup the service clients for the tests"""
         super(ScenarioTest, cls).setup_clients()
-        # Clients (in alphabetical order)
         cls.flavors_client = cls.os_primary.flavors_client
         cls.compute_floating_ips_client = (
             cls.os_primary.compute_floating_ips_client)
@@ -108,37 +130,20 @@
                 raise lib_exc.InvalidConfiguration(
                     'Either api_v1 or api_v2 must be True in '
                     '[image-feature-enabled].')
-        # Compute image client
-        cls.compute_images_client = cls.os_primary.compute_images_client
-        cls.keypairs_client = cls.os_primary.keypairs_client
-        # Nova security groups client
-        cls.compute_security_groups_client = (
-            cls.os_primary.compute_security_groups_client)
-        cls.compute_security_group_rules_client = (
-            cls.os_primary.compute_security_group_rules_client)
-        cls.servers_client = cls.os_primary.servers_client
-        cls.interface_client = cls.os_primary.interfaces_client
-        # Neutron network client
-        cls.networks_client = cls.os_primary.networks_client
-        cls.ports_client = cls.os_primary.ports_client
-        cls.routers_client = cls.os_primary.routers_client
-        cls.subnets_client = cls.os_primary.subnets_client
-        cls.floating_ips_client = cls.os_primary.floating_ips_client
-        cls.security_groups_client = cls.os_primary.security_groups_client
-        cls.security_group_rules_client = (
-            cls.os_primary.security_group_rules_client)
-        # Use the latest available volume clients
+
+        cls.setup_compute_client(cls)
+        cls.setup_network_client(cls)
         if CONF.service_available.cinder:
             cls.volumes_client = cls.os_primary.volumes_client_latest
             cls.snapshots_client = cls.os_primary.snapshots_client_latest
             cls.backups_client = cls.os_primary.backups_client_latest
 
     # ## Test functions library
-    #
     # The create_[resource] functions only return body and discard the
     # resp part which is not used in scenario tests
 
     def create_port(self, network_id, client=None, **kwargs):
+        """Creates port"""
         if not client:
             client = self.ports_client
         name = data_utils.rand_name(self.__class__.__name__)
@@ -156,6 +161,13 @@
         return port
 
     def create_keypair(self, client=None):
+        """Creates keypair
+
+        Keypair is a public key of OpenSSH key pair used for accessing
+        and create servers
+        Keypair can also be created by a private key for the same purpose
+        Here, the keys are randomly generated[public/private]
+        """
         if not client:
             client = self.keypairs_client
         name = data_utils.rand_name(self.__class__.__name__)
@@ -295,6 +307,13 @@
 
     def create_volume(self, size=None, name=None, snapshot_id=None,
                       imageRef=None, volume_type=None):
+        """Creates volume
+
+        This wrapper utility creates volume and waits for volume to be
+        in 'available' state.
+        This method returns the volume's full representation by GET request.
+        """
+
         if size is None:
             size = CONF.volume.volume_size
         if imageRef:
@@ -334,6 +353,11 @@
     def create_backup(self, volume_id, name=None, description=None,
                       force=False, snapshot_id=None, incremental=False,
                       container=None):
+        """Creates backup
+
+        This wrapper utility creates backup and waits for backup to be
+        in 'available' state.
+        """
 
         name = name or data_utils.rand_name(
             self.__class__.__name__ + "-backup")
@@ -351,6 +375,12 @@
         return backup
 
     def restore_backup(self, backup_id):
+        """Restore backup
+
+        This wrapper utility restores backup and waits for backup to be
+        in 'available' state.
+        """
+
         restore = self.backups_client.restore_backup(backup_id)['restore']
         self.addCleanup(self.volumes_client.delete_volume,
                         restore['volume_id'])
@@ -362,8 +392,31 @@
         self.assertEqual(backup_id, restore['backup_id'])
         return restore
 
+    def rebuild_server(self, server_id, image=None,
+                       preserve_ephemeral=False, wait=True,
+                       rebuild_kwargs=None):
+        if image is None:
+            image = CONF.compute.image_ref
+        rebuild_kwargs = rebuild_kwargs or {}
+        LOG.debug("Rebuilding server (id: %s, image: %s, preserve eph: %s)",
+                  server_id, image, preserve_ephemeral)
+        self.servers_client.rebuild_server(
+            server_id=server_id,
+            image_ref=image,
+            preserve_ephemeral=preserve_ephemeral,
+            **rebuild_kwargs)
+        if wait:
+            waiters.wait_for_server_status(self.servers_client,
+                                           server_id, 'ACTIVE')
+
     def create_volume_snapshot(self, volume_id, name=None, description=None,
                                metadata=None, force=False):
+        """Creates volume
+
+        This wrapper utility creates volume snapshot and waits for backup
+        to be in 'available' state.
+        """
+
         name = name or data_utils.rand_name(
             self.__class__.__name__ + '-snapshot')
         snapshot = self.snapshots_client.create_snapshot(
@@ -372,6 +425,7 @@
             display_name=name,
             description=description,
             metadata=metadata)['snapshot']
+
         self.addCleanup(self.snapshots_client.wait_for_resource_deletion,
                         snapshot['id'])
         self.addCleanup(self.snapshots_client.delete_snapshot, snapshot['id'])
@@ -401,6 +455,23 @@
         admin_volume_type_client.delete_volume_type(volume_type['id'])
 
     def create_volume_type(self, client=None, name=None, backend_name=None):
+        """Creates volume type
+
+        In a multiple-storage back-end configuration,
+        each back end has a name (volume_backend_name).
+        The name of the back end is declared as an extra-specification
+        of a volume type (such as, volume_backend_name=LVM).
+        When a volume is created, the scheduler chooses an
+        appropriate back end to handle the request, according
+        to the volume type specified by the user.
+        The scheduler uses volume types to explicitly create volumes on
+        specific back ends.
+
+        Before using volume type, a volume type has to be declared
+        to Block Storage. In addition to that, an extra-specification
+        has to be created to link the volume type to a back end name.
+        """
+
         if not client:
             client = self.os_admin.volume_types_client_latest
         if not name:
@@ -416,6 +487,7 @@
 
         volume_type = client.create_volume_type(
             name=randomized_name, extra_specs=extra_specs)['volume_type']
+        self.assertIn('id', volume_type)
         self.addCleanup(self._cleanup_volume_type, volume_type)
         return volume_type
 
@@ -456,7 +528,7 @@
         return rules
 
     def _create_security_group(self):
-        # Create security group
+        """Create security group and add rules to security group"""
         sg_name = data_utils.rand_name(self.__class__.__name__)
         sg_desc = sg_name + " description"
         secgroup = self.compute_security_groups_client.create_security_group(
@@ -470,7 +542,6 @@
 
         # Add rules to the security group
         self._create_loginable_secgroup_rule(secgroup['id'])
-
         return secgroup
 
     def get_remote_client(self, ip_address, username=None, private_key=None,
@@ -555,6 +626,7 @@
         return image['id']
 
     def _log_console_output(self, servers=None, client=None):
+        """Console log output"""
         if not CONF.compute_feature_enabled.console_output:
             LOG.debug('Console output not supported, cannot log')
             return
@@ -573,11 +645,12 @@
                           "for the console log", server['id'])
 
     def _log_net_info(self, exc):
-        # network debug is called as part of ssh init
+        """network debug is called as part of ssh init"""
         if not isinstance(exc, lib_exc.SSHTimeout):
             LOG.debug('Network information on a devstack host')
 
     def create_server_snapshot(self, server, name=None):
+        """Creates server snapshot"""
         # Glance client
         _image_client = self.image_client
         # Compute client
@@ -595,7 +668,7 @@
                         _image_client.delete_image, image_id)
 
         if CONF.image_feature_enabled.api_v1:
-            # In glance v1 the additional properties are stored in the headers.
+            # In glance v1 the additional properties are stored in the headers
             resp = _image_client.check_image(image_id)
             snapshot_image = common_image.get_image_meta_from_headers(resp)
             image_props = snapshot_image.get('properties', {})
@@ -625,6 +698,7 @@
         return snapshot_image
 
     def nova_volume_attach(self, server, volume_to_attach):
+        """Attach nova volume"""
         volume = self.servers_client.attach_volume(
             server['id'], volumeId=volume_to_attach['id'])['volumeAttachment']
         self.assertEqual(volume_to_attach['id'], volume['id'])
@@ -635,12 +709,14 @@
         return self.volumes_client.show_volume(volume['id'])['volume']
 
     def nova_volume_detach(self, server, volume):
+        """Detach nova volume"""
         self.servers_client.detach_volume(server['id'], volume['id'])
         waiters.wait_for_volume_resource_status(self.volumes_client,
                                                 volume['id'], 'available')
 
     def ping_ip_address(self, ip_address, should_succeed=True,
                         ping_timeout=None, mtu=None, server=None):
+        """ping ip address"""
         timeout = ping_timeout or CONF.validation.ping_timeout
         cmd = ['ping', '-c1', '-w1']
 
@@ -701,6 +777,7 @@
         :raises: AssertError if the result of the connectivity check does
             not match the value of the should_connect param
         """
+
         LOG.debug('checking network connections to IP %s with user: %s',
                   ip_address, username)
         if should_connect:
@@ -724,7 +801,7 @@
                 LOG.exception(extra_msg)
                 raise
 
-    def create_floating_ip(self, thing, pool_name=None):
+    def create_floating_ip(self, server, pool_name=None):
         """Create a floating IP and associates to a server on Nova"""
 
         if not pool_name:
@@ -735,11 +812,17 @@
                         self.compute_floating_ips_client.delete_floating_ip,
                         floating_ip['id'])
         self.compute_floating_ips_client.associate_floating_ip_to_server(
-            floating_ip['ip'], thing['id'])
+            floating_ip['ip'], server['id'])
         return floating_ip
 
     def create_timestamp(self, ip_address, dev_name=None, mount_path='/mnt',
                          private_key=None, server=None):
+        """Creates timestamp
+
+        This wrapper utility does ssh, creates timestamp and returns the
+        created timestamp.
+        """
+
         ssh_client = self.get_remote_client(ip_address,
                                             private_key=private_key,
                                             server=server)
@@ -757,6 +840,11 @@
 
     def get_timestamp(self, ip_address, dev_name=None, mount_path='/mnt',
                       private_key=None, server=None):
+        """Returns timestamp
+
+        This wrapper utility does ssh and returns the timestamp.
+        """
+
         ssh_client = self.get_remote_client(ip_address,
                                             private_key=private_key,
                                             server=server)
@@ -774,6 +862,7 @@
         Based on the configuration we're in, return a correct ip
         address for validating that a guest is up.
         """
+
         if CONF.validation.connect_method == 'floating':
             # The tests calling this method don't have a floating IP
             # and can't make use of the validation resources. So the
@@ -799,6 +888,8 @@
 
     @classmethod
     def get_host_for_server(cls, server_id):
+        """Gets host of server"""
+
         server_details = cls.os_admin.servers_client.show_server(server_id)
         return server_details['server']['OS-EXT-SRV-ATTR:host']
 
@@ -817,6 +908,12 @@
                                     security_group=None,
                                     delete_on_termination=False,
                                     name=None):
+        """Boot instance from resource
+
+        This wrapper utility boots instance from resource with block device
+        mapping with source info passed in arguments
+        """
+
         create_kwargs = dict()
         if keypair:
             create_kwargs['key_name'] = keypair['name']
@@ -833,6 +930,7 @@
         return self.create_server(image_id='', **create_kwargs)
 
     def create_volume_from_image(self):
+        """Create volume from image"""
         img_uuid = CONF.compute.image_ref
         vol_name = data_utils.rand_name(
             self.__class__.__name__ + '-volume-origin')
@@ -888,8 +986,17 @@
                       namestart='subnet-smoke', **kwargs):
         """Create a subnet for the given network
 
+        This utility creates subnet for the given network
         within the cidr block configured for tenant networks.
+
+        :param **kwargs:
+            See extra parameters below
+
+        :Keyword Arguments:
+
+            * *ip_version = ip version of the given network,
         """
+
         if not subnets_client:
             subnets_client = self.subnets_client
 
@@ -992,22 +1099,23 @@
                             "Unable to get network by name: %s" % network_name)
         return net[0]
 
-    def create_floating_ip(self, thing, external_network_id=None,
+    def create_floating_ip(self, server, external_network_id=None,
                            port_id=None, client=None):
         """Create a floating IP and associates to a resource/port on Neutron"""
+
         if not external_network_id:
             external_network_id = CONF.network.public_network_id
         if not client:
             client = self.floating_ips_client
         if not port_id:
-            port_id, ip4 = self._get_server_port_id_and_ip4(thing)
+            port_id, ip4 = self._get_server_port_id_and_ip4(server)
         else:
             ip4 = None
 
         kwargs = {
             'floating_network_id': external_network_id,
             'port_id': port_id,
-            'tenant_id': thing.get('project_id') or thing['tenant_id'],
+            'tenant_id': server.get('project_id') or server['tenant_id'],
             'fixed_ip_address': ip4,
         }
         if CONF.network.subnet_id:
@@ -1027,6 +1135,7 @@
         :param status: target status
         :raises: AssertionError if status doesn't match
         """
+
         floatingip_id = floating_ip['id']
 
         def refresh():
@@ -1053,6 +1162,7 @@
                                           private_key,
                                           should_connect=True,
                                           servers_for_debug=None):
+        """Checks tenant network connectivity"""
         if not CONF.network.project_networks_reachable:
             msg = 'Tenant networks not configured to be reachable.'
             LOG.info(msg)
@@ -1085,6 +1195,7 @@
         :returns: True, if the connection succeeded and it was expected to
             succeed. False otherwise.
         """
+
         method_name = '%s_check' % protocol
         connectivity_checker = getattr(source, method_name)
 
@@ -1148,6 +1259,7 @@
         :param project_id: secgroup will be created in this project
         :returns: the created security group
         """
+
         if client is None:
             client = self.security_groups_client
         if not project_id:
@@ -1189,6 +1301,7 @@
                     port_range_max: 22
                     }
         """
+
         if sec_group_rules_client is None:
             sec_group_rules_client = self.security_group_rules_client
         if security_groups_client is None:
@@ -1279,6 +1392,7 @@
         network has, a tenant router will be created and returned that
         routes traffic to the public network.
         """
+
         if not client:
             client = self.routers_client
         if not project_id:
@@ -1319,6 +1433,7 @@
                                    'provider:segmentation_id': '42'}
         :returns: network, subnet, router
         """
+
         if CONF.network.shared_physical_network:
             # NOTE(Shrews): This exception is for environments where tenant
             # credential isolation is available, but network separation is
@@ -1375,6 +1490,7 @@
     def create_encryption_type(self, client=None, type_id=None, provider=None,
                                key_size=None, cipher=None,
                                control_location=None):
+        """Creates an encryption type for volume"""
         if not client:
             client = self.admin_encryption_types_client
         if not type_id:
@@ -1388,6 +1504,7 @@
     def create_encrypted_volume(self, encryption_provider, volume_type,
                                 key_size=256, cipher='aes-xts-plain64',
                                 control_location='front-end'):
+        """Creates an encrypted volume"""
         volume_type = self.create_volume_type(name=volume_type)
         self.create_encryption_type(type_id=volume_type['id'],
                                     provider=encryption_provider,
@@ -1428,11 +1545,12 @@
         cls.object_client = cls.os_operator.object_client
 
     def get_swift_stat(self):
-        """get swift status for our user account."""
+        """Get swift status for our user account."""
         self.account_client.list_account_containers()
         LOG.debug('Swift status information obtained successfully')
 
     def create_container(self, container_name=None):
+        """Creates container"""
         name = container_name or data_utils.rand_name(
             'swift-scenario-container')
         self.container_client.update_container(name)
@@ -1445,10 +1563,12 @@
         return name
 
     def delete_container(self, container_name):
+        """Deletes container"""
         self.container_client.delete_container(container_name)
         LOG.debug('Container %s deleted', container_name)
 
     def upload_object_to_container(self, container_name, obj_name=None):
+        """Uploads object to container"""
         obj_name = obj_name or data_utils.rand_name('swift-scenario-object')
         obj_data = data_utils.random_bytes()
         self.object_client.create_object(container_name, obj_name, obj_data)
@@ -1459,6 +1579,7 @@
         return obj_name, obj_data
 
     def delete_object(self, container_name, filename):
+        """Deletes object"""
         self.object_client.delete_object(container_name, filename)
         self.list_and_check_container_objects(container_name,
                                               not_present_obj=[filename])
@@ -1466,8 +1587,13 @@
     def list_and_check_container_objects(self, container_name,
                                          present_obj=None,
                                          not_present_obj=None):
-        # List objects for a given container and assert which are present and
-        # which are not.
+        """List and verify objects for a given container
+
+        This utility lists objects for a given container
+        and asserts which are present and
+        which are not
+        """
+
         if present_obj is None:
             present_obj = []
         if not_present_obj is None:
@@ -1482,5 +1608,6 @@
                 self.assertNotIn(obj, object_list)
 
     def download_and_verify(self, container_name, obj_name, expected_data):
+        """Asserts the object and expected data to verify if they are same"""
         _, obj = self.object_client.get_object(container_name, obj_name)
         self.assertEqual(obj, expected_data)