Adds ability to set no-resolv for dnsmasq.

Introduces variable neutron_dnsmasq_noresolv. When it is set to true,
no-resolv option will be placed in dnsmasq-neutron.conf.

If dnsmasq_dns_servers are not set, and neutron_dnsmasq_noresolv is True
dnsmasq will reply with empty response on DNS requests,
which may be used as a workaround of
https://bugs.launchpad.net/neutron/+bug/1501206
As a con, resolver is actually won't work at all, so all networks w/o
configured DNS will stop resolving DNS.

Change-Id: I7764e0d6100a8327f84f78da64f10f8e1fa355b1

defaults/main.yml

@@ -132,6 +132,12 @@ neutron_dns_domain: "openstacklocal."
 neutron_dhcp_config:
   log-facility: "{{ neutron_log_dir }}/neutron-dnsmasq.log"
 
+# Disable dnsmasq to resolve DNS via local resolv.conf.
+# When dnsmasq_dns_servers are not set,
+# and neutron_dnsmasq_noresolv is set to True, dnsmasq will reply with
+# empty respose on DNS requests.
+neutron_dnsmasq_noresolv: False
+
 # Set the neutron lbaasv2 user group, defaults from os specific vars
 neutron_lbaasv2_user_group: "{{ _neutron_lbaasv2_user_group }}"
 

templates/dnsmasq-neutron.conf.j2

@@ -4,3 +4,6 @@
 {{ key }}={{ value }}
 {% endfor %}
 user={{ neutron_system_user_name }}
+{% if neutron_dnsmasq_noresolv %}
+no-resolv
+{% endif %}