Dockerfile improvements.

ansible/playbook.yml

@@ -6,7 +6,12 @@
   become: true
   vars_files:
     - vars/default.yml
-    - "{{ var_file }}"
+
+  pre_tasks:
+    - name: Load per-host vars file from inventory (var_file)
+      ansible.builtin.include_vars:
+        file: "{{ var_file }}"
+      when: var_file is defined
 
   roles:
     - network