diff --git a/tacker/vm/hosting_device_scheduler.py b/tacker/vm/hosting_device_scheduler.py
new file mode 100644
index 000000000..a14398109
--- /dev/null
+++ b/tacker/vm/hosting_device_scheduler.py
@@ -0,0 +1,130 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+#
+# Copyright 2013, 2014 Intel Corporation.
+# Copyright 2013, 2014 Isaku Yamahata <isaku.yamahata at intel com>
+#                                     <isaku.yamahata at gmail com>
+# All Rights Reserved.
+#
+#
+#    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.
+#
+# @author: Isaku Yamahata, Intel Corporation.
+
+import random
+
+import sqlalchemy as sa
+
+from tacker.db.vm import vm_db
+from tacker.openstack.common import log as logging
+from tacker.plugins.common import constants
+
+
+LOG = logging.getLogger(__name__)
+
+
+class ChanceScheduler(object):
+
+    """Select a Device that can serve a service in a random way."""
+
+    def schedule(self, plugin, context,
+                 service_type, service_instance_id, name, service_context):
+        """
+        :param service_context: list of DeviceServiceContext
+                                without service_instance_id
+        [{'network_id': network_id,
+          'subnet_id': subnet_id,
+          'port_id': port_id,
+          'router_id': router_id,
+          'role': role,
+          'index': index},
+        ... ]
+        They can be missing or None = don't care
+        """
+        with context.session.begin(subtransactions=True):
+            # Race. prevent from inserting ServiceDeviceBinding
+
+            # select hosting device that is capable of service_type, but
+            # not yet used for it.
+            # i.e.
+            # device.service_type in
+            #     [st.service_types for st in
+            #      device.template.service_types]
+            # and
+            # device.sevice_type not in
+            #     [ls.service_type for ls in device.services]
+            query = (
+                context.session.query(vm_db.Device).
+                filter(vm_db.Device.status == constants.ACTIVE).
+                filter(
+                    sa.exists().
+                    where(sa.and_(
+                        vm_db.Device.template_id == vm_db.DeviceTemplate.id,
+                        vm_db.DeviceTemplate.id ==
+                        vm_db.ServiceType.template_id,
+                        vm_db.ServiceType.service_type == service_type))).
+                filter(
+                    ~sa.exists().
+                    where(sa.and_(
+                        vm_db.Device.id ==
+                        vm_db.ServiceDeviceBinding.device_id,
+                        vm_db.ServiceDeviceBinding.service_instance_id ==
+                        vm_db.ServiceInstance.id,
+                        vm_db.ServiceInstance.service_type_id ==
+                        vm_db.ServiceType.id,
+                        vm_db.ServiceType.service_type == service_type))))
+
+            for sc_entry in service_context:
+                network_id = sc_entry.get('network_id')
+                subnet_id = sc_entry.get('subnet_id')
+                port_id = sc_entry.get('port_id')
+                router_id = sc_entry.get('router_id')
+                role = sc_entry.get('role')
+                index = sc_entry.get('index')
+
+                expr = [
+                    vm_db.Device.id == vm_db.DeviceServiceContext.device_id]
+                if network_id is not None:
+                    expr.append(
+                        vm_db.DeviceServiceContext.network_id == network_id)
+                if subnet_id is not None:
+                    expr.append(
+                        vm_db.DeviceServiceContext.subnet_id == subnet_id)
+                if port_id is not None:
+                    expr.append(vm_db.DeviceServiceContext.port_id == port_id)
+                if router_id is not None:
+                    expr.append(
+                        vm_db.DeviceServiceContext.router_id == router_id)
+                if role is not None:
+                    expr.append(vm_db.DeviceServiceContext.role == role)
+                if index is not None:
+                    expr.append(vm_db.DeviceServiceContext.index == index)
+                query = query.filter(sa.exists().where(sa.and_(*expr)))
+
+            candidates = query.with_lockmode("update").all()
+            if not candidates:
+                LOG.debug(_('no hosting device supporing %s'), service_type)
+                return
+            device = random.choice(candidates)
+
+            service_type_id = [s.id for s in device.template.service_types
+                               if s.service_type == service_type][0]
+
+            service_instance_param = {
+                'name': name,
+                'service_table_id': service_instance_id,
+                'service_type': service_type,
+                'service_type_id': service_type_id,
+            }
+            service_instance_dict = plugin._create_service_instance(
+                context, device.id, service_instance_param, False)
+            return (plugin._make_device_dict(device), service_instance_dict)