无法创建网络，大神们帮忙看看啊！

    先谢谢各位了，下面是我遇到的问题。
    刚开始学习openstack，按照官方文档搭建了一个测试环境，系统为:ubuntu 14.04 openstack版本：mitaka，比较顺利的安装了keystone,compute,neutron以及horizon。
    但是，进入dashboard后，无法创建网络，如图：


看neutron-server.log日志有报错：
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource [req-c9c7da97-721e-41d1-8522-acba1966bc69 67c2ced908cb47f9be82a21b2f6935bd 7a29993a3ac94f59bb461b9fdd65c6f6 - - -] create failed
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource Traceback (most recent call last):
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/api/v2/resource.py", line 84, in resource
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     result = method(request=request, **args)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/api/v2/base.py", line 410, in create
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     return self._create(request, body, **kwargs)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/oslo_db/api.py", line 148, in wrapper
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     ectxt.value = e.inner_exc
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 220, in __exit__
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     self.force_reraise()
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     six.reraise(self.type_, self.value, self.tb)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/oslo_db/api.py", line 138, in wrapper
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     return f(*args, **kwargs)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/api/v2/base.py", line 521, in _create
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     obj = do_create(body)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/api/v2/base.py", line 503, in do_create
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     request.context, reservation.reservation_id)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 220, in __exit__
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     self.force_reraise()
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     six.reraise(self.type_, self.value, self.tb)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/api/v2/base.py", line 496, in do_create
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     return obj_creator(request.context, **kwargs)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/plugins/ml2/plugin.py", line 696, in create_network
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     result, mech_context = self._create_network_db(context, network)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/plugins/ml2/plugin.py", line 668, in _create_network_db
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     tenant_id)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/plugins/ml2/managers.py", line 208, in create_network_segments
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     segment = self._allocate_tenant_net_segment(session)
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource   File "/usr/lib/python2.7/dist-packages/neutron/plugins/ml2/managers.py", line 244, in _allocate_tenant_net_segment
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource     raise exc.NoNetworkAvailable()
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource NoNetworkAvailable: Unable to create the network. No tenant network is available for allocation.
2016-07-13 16:55:21.337 2205 ERROR neutron.api.v2.resource

1.先检测neutron服务组件是否正常
2.楼主在创建什么网络，是网络实例，还是什么。
3.初步判断 应该neutron-server的问题

network_vlan_ranges这个选项配置和你horizon创建网络的时候选的类型不一样，再仔细看看配置，对照下

先检查neutron-server有没有错误