DNS resolver
http://docs.openstack.org/mitaka/networking-guide/config-dns-resolution.html



# neutron subnet-show a0f5cdaa-c813-47b0-ae68-5caba22be3a6+-------------------+------------------------------------------------+
| Field             | Value                                          |
+-------------------+------------------------------------------------+
| allocation_pools  | {"start": "172.16.1.2", "end": "172.16.1.254"} |
| cidr              | 172.16.1.0/24                                  |
| created_at        | 2016-08-09T05:34:09                            |
| description       |                                                |
| dns_nameservers   | 115.XXX.XXX.210                                  |
| enable_dhcp       | True                                           |
| gateway_ip        | 172.16.1.1                                     |
| host_routes       |                                                |
| id                | a0f5cdaa-c813-47b0-ae68-5caba22be3a6           |
| ip_version        | 4                                              |
| ipv6_address_mode |                                                |
| ipv6_ra_mode      |                                                |
| name              | leekh_private                                  |
| network_id        | 85471ab1-9631-4e14-bf75-405b76ebaae2           |
| subnetpool_id     |                                                |
| tenant_id         | 41c44757fdf74890b7a8dbd7ace74d4e               |
| updated_at        | 2016-08-10T08:43:32                            |
+-------------------+------------------------------------------------+

:: DNS 1개 수정
# neutron subnet-update a0f5cdaa-c813-47b0-ae68-5caba22be3a6 --dns-nameserver 164.124.101.2
Updated subnet: 3a002668-592c-44d1-81d9-1fe666cd207c

:: DNS 2개 이상 수정 
API   
--dns-nameserver 항목에 배열로 입력
# curl -g -i -X PUT http://con-201-54:9696/v2.0/subnets/a0f5cdaa-c813-47b0-ae68-5caba22be3a6.json -H "User-Agent: python-neutronclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: {SHA1}07176ff28773f5eb994790d2228ca4c155192da7" -d '{"subnet": {"dns_nameservers": ["8.8.8.8", "8.8.4.4"]}}'

# neutron subnet-update a0f5cdaa-c813-47b0-ae68-5caba22be3a6 --dns-nameservers list=true 8.8.8.8 8.8.4.4
# neutron subnet-show a0f5cdaa-c813-47b0-ae68-5caba22be3a6+-------------------+------------------------------------------------+
| Field             | Value                                          |
+-------------------+------------------------------------------------+
| allocation_pools  | {"start": "172.16.1.2", "end": "172.16.1.254"} |
| cidr              | 172.16.1.0/24                                  |
| created_at        | 2016-08-09T05:34:09                            |
| description       |                                                |
| dns_nameservers   | 8.8.8.8                                        |
|                   | 8.8.4.4                                        |
| enable_dhcp       | True                                           |
| gateway_ip        | 172.16.1.1                                     |
| host_routes       |                                                |
| id                | a0f5cdaa-c813-47b0-ae68-5caba22be3a6           |
| ip_version        | 4                                              |
| ipv6_address_mode |                                                |
| ipv6_ra_mode      |                                                |
| name              | leekh_private                                  |
| network_id        | 85471ab1-9631-4e14-bf75-405b76ebaae2           |
| subnetpool_id     |                                                |
| tenant_id         | 41c44757fdf74890b7a8dbd7ace74d4e               |
| updated_at        | 2016-08-10T08:59:40                            |
+-------------------+------------------------------------------------+

참고
https://ask.openstack.org/en/question/26278/neutron-dhcp-adding-dns/