Add rfc1918 healthcheck

Ensure that you are using an rfc1918 internally.
If you are using one, you must be aware of what you are doing,
and deploy your own haproxy, or override the acls.

Change-Id: I2e3b38892c194c8be289bd18f244d779f59e1aaf

playbooks/healthcheck-hosts.yml

@@ -56,6 +56,15 @@
       environment: "{{ deployment_environment_variables | default({}) }}"
 
 # Test extra settings before setup-infrastructure
+- name: Ensure the internal_interfaces are well in the right range
+  hosts: localhost
+  gather_facts: no
+  tasks:
+    - name: Check your internal network is using private ips
+      assert:
+        that:
+          - internal_lb_vip_address | ipaddr('private')
+
 - name: Ensure settings are not wrong with the usual suspects issues before trying to deploy infra
   hosts: haproxy
   gather_facts: yes