diff --git a/zaza/configure/guest.py b/zaza/configure/guest.py
index e99ce5f..d878191 100644
--- a/zaza/configure/guest.py
+++ b/zaza/configure/guest.py
@@ -36,11 +36,26 @@ boot_tests = {
         'bootstring': 'finished at'}}
 
 
-def launch_instance(instance_key):
+def launch_instance(instance_key, use_boot_volume=False, vm_name=None,
+                    private_network_name=None, image_name=None,
+                    flavor_name=None, external_network_name=None):
     """Launch an instance.
 
     :param instance_key: Key to collect associated config data with.
     :type instance_key: str
+    :param use_boot_volume: Whether to boot guest from a shared volume.
+    :type use_boot_volume: boolean
+    :param vm_name: Name to give guest.
+    :type vm_name: str
+    :param private_network_name: Name of private network to attach guest to.
+    :type private_network_name: str
+    :param image_name: Image name to use with guest.
+    :type image_name: str
+    :param flavor_name: Flavor name to use with guest.
+    :type flavor_name: str
+    :param external_network_name: External network to create floating ip from
+                                  for guest.
+    :type external_network_name: str
     """
     keystone_session = openstack_utils.get_overcloud_keystone_session()
     nova_client = openstack_utils.get_nova_session_client(keystone_session)
@@ -48,19 +63,38 @@ def launch_instance(instance_key):
         keystone_session)
 
     # Collect resource information.
-    vm_name = time.strftime("%Y%m%d%H%M%S")
-    image = nova_client.glance.find_image(
-        boot_tests[instance_key]['image_name'])
-    flavor = nova_client.flavors.find(
-        name=boot_tests[instance_key]['flavor_name'])
-    net = neutron_client.find_resource("network", "private")
+    vm_name = vm_name or time.strftime("%Y%m%d%H%M%S")
+
+    image_name = image_name or boot_tests[instance_key]['image_name']
+    image = nova_client.glance.find_image(image_name)
+
+    flavor_name = flavor_name or boot_tests[instance_key]['flavor_name']
+    flavor = nova_client.flavors.find(name=flavor_name)
+
+    private_network_name = private_network_name or "private"
+    net = neutron_client.find_resource("network", private_network_name)
     nics = [{'net-id': net.get('id')}]
 
+    external_network_name = external_network_name or "ext_net"
+
+    if use_boot_volume:
+        bdmv2 = [{
+            'boot_index': '0',
+            'uuid': image.id,
+            'source_type': 'image',
+            'volume_size': flavor.disk,
+            'destination_type': 'volume',
+            'delete_on_termination': True}]
+        image = None
+    else:
+        bdmv2 = None
+
     # Launch instance.
     logging.info('Launching instance {}'.format(vm_name))
     instance = nova_client.servers.create(
         name=vm_name,
         image=image,
+        block_device_mapping_v2=bdmv2,
         flavor=flavor,
         key_name=nova_utils.KEYPAIR_NAME,
         nics=nics)
@@ -83,7 +117,7 @@ def launch_instance(instance_key):
     logging.info('Assigning floating ip.')
     ip = openstack_utils.create_floating_ip(
         neutron_client,
-        "ext_net",
+        external_network_name,
         port=port)['floating_ip_address']
     logging.info('Assigned floating IP {} to {}'.format(ip, vm_name))
     openstack_utils.ping_response(ip)