We created experimental Neutron DVR+HA multinode job with [1].
DVR+HA needs a three node setup with two dvr_snat nodes
and one dvr node. So in this setup, we set
1) controller node's agent_mode to dvr_snat
2) first compute to dvr and other to dvr_snat
[1] https://review.openstack.org/#/c/383742/
Change-Id: I4e08a97158dc4538c6f021c049c6e60fb7293459