要启用 DVR，比较简单，分别在各个节点的网络配置文件上做如下修改或添加。
/etc/neutron/neutron.conf
router_distributed = True/etc/neutron/l3_agent.ini
agent_mode = [dvr_snat | dvr | legacy ]网络节点上配置为 dvr_snat，计算节点上配置为 dvr。
/etc/neutron/plugins/ml2/ml2_conf.ini
[ml2]
mechanism_drivers = openvswitch,linuxbridge,l2population
[agent]
l2_population = True
tunnel_types = vxlan
enable_distributed_routing = True