use the resolveHosts role to allow nodes to resolve other nodes by name....

use the resolveHosts role to allow nodes to resolve other nodes by name. conifugre the dependenices for resolveHosts to use the role etcHosts if you would like to put all hosts in /etc/hosts or create a new role for a dnsclient if you would prefer

roles/commonVars/vars/main.yml

+---
+domain: testdomain.massive.org.au

roles/etcHosts/tasks/main.yml

+- name: get_groups_json
+  template: dest=/tmp/groups src=groups.j2
+  run_once: True
+  delegate_to: 127.0.0.1
+
+- name: make hosts data
+  command: ./scripts/makehosts.py /tmp/groups {{ domain }}
+  delegate_to: 127.0.0.1
+  run_once: True
+  register: hosts_data
+               
+- name: write hosts file
+  lineinfile:
+  args:
+    dest: /etc/hosts
+    line: "{{ item }}"
+    state: present
+  sudo: true
+  with_items: hosts_data.stdout_lines

roles/etcHosts/templates/groups.j2

+{ 
+  "groups": {{ groups | to_nice_json }},
+  "hostvars": {{ hostvars | to_nice_json }}
+}

roles/resolveHosts/meta/main.yml

+---
+dependencies:
+  - { role: commonVars }
+  - { role: etcHosts }
+