Verifies correct parameter is given

local.yml

@@ -1,3 +1,14 @@
+- hosts: localhost
+  gather_facts: no
+  tasks:
+
+  - name: Verify correct usage of parameter
+    assert:
+      that:
+        - nombre is defined
+        - nombre|length > 3
+      fail_msg: 'Debe definir una variable "nombre"'
+
 - hosts: localhost
   gather_facts: yes
   user: sistemas
@@ -10,3 +21,5 @@
   gather_facts: no
   roles:
     - nginxproxy
+  vars:
+    dominio: agofer.net

roles/nginxproxy/vars/main.yml

@@ -1,4 +1,2 @@
 ---
 email: sistemas@agofer.com.co
-
-dominio: agofer.net