change the task names to help debuging if there is a problem

roles/lmod/tasks/main.yml

 ---
 - include_vars: "{{ ansible_os_family }}.yml"
 
-- name: install lua
-  yum: name={{ item }} state=installed
+- name: install lua centos
+  yum: name={{ item }} state=installed update_cache=yes
   with_items:
     - lua
     - lua-filesystem
@@ -14,7 +14,7 @@
   sudo: true
   when: ansible_os_family == 'RedHat'
 
-- name: install lua
+- name: install lua debian
   apt: name={{ item }} state=installed
   with_items:
     - lua5.2