Extending designate named template to include "forwarders" parameter

To get forwarding to work in the kolla implementaion of designate,
I'm adding parameters to the named.conf.j2 template.  I'm adding
the ability to change the default values for dnssec-validation and
recursion and creating a new paramater for forwarders.

Change-Id: Ideef39034d75a0d99e8a3dc2a5f1a7203ccf51d5
Closes-Bug: #1781196

ansible/roles/designate/defaults/main.yml

@@ -140,3 +140,11 @@ openstack_designate_auth: "{{ openstack_auth }}"
 designate_git_repository: "{{ kolla_dev_repos_git }}/{{ project_name }}"
 designate_dev_repos_pull: "{{ kolla_dev_repos_pull }}"
 designate_dev_mode: "{{ kolla_dev_mode }}"
+
+####################
+## Designate
+#####################
+designate_dnssec_validation: "yes"
+designate_recursion: "no"
+## Example for designate_forwarders_addresses: "10.199.200.1; 10.199.100.1"
+designate_forwarders_addresses: ""

ansible/roles/designate/templates/named.conf.j2

@@ -3,10 +3,11 @@ options {
         listen-on port {{ designate_bind_port }} { {{ hostvars[inventory_hostname]['ansible_' + hostvars[inventory_hostname]['api_interface']]['ipv4']['address'] }}; };
         directory       "/var/lib/named";
         allow-new-zones yes;
-        dnssec-validation auto;
+        dnssec-validation {{ designate_dnssec_validation }};
         auth-nxdomain no;
         request-ixfr no;
-        recursion no;
+        recursion {{ designate_recursion }};
+        forwarders { {{ designate_forwarders_addresses }}; };
         minimal-responses yes;
         allow-notify { {% for host in groups['designate-worker'] %}{{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }};{% endfor %} };
 };