fix: refactor dynmaic vars file loading

tasks/main.yml

@@ -1,13 +1,15 @@
 ---
-- include_vars: "{{ lookup('first_found', params) }}"
+- include_vars: "{{ var_files }}"
   vars:
+    var_files: "{{ lookup('first_found', params, errors='ignore') }}"
     params:
       files:
         - "{{ ansible_lsb.id | default('') | lower }}.yml"
+        - "{{ ansible_os_family | lower }}-{{ ansible_distribution_major_version }}.yml"
         - "{{ ansible_os_family | lower }}.yml"
-        - default.yml
       paths:
         - "vars"
+  when: var_files
 
 - include_tasks: install.yml
 

vars/redhat.yml

@@ -0,0 +1,8 @@
+---
+__postfix_relay_packages:
+  - postfix
+  - cyrus-sasl-plain
+  - mailx
+
+__postfix_relay_daemon_directory: /usr/libexec/postfix
+__postfix_relay_smtp_tls_cafile: /etc/ssl/certs/ca-bundle.crt