Prevent cloud-init from overwriting hostname

roles/instance/tasks/main.yml

@@ -3,6 +3,19 @@
   hostname:
     name: '{{ inventory_hostname | replace("_", "-") }}'
 
+- name: check if rules file exists
+  stat:
+    path: /etc/cloud/cloud.cfg
+  register: cloud_cfg
+
+- name: Prevent cloud-init hostname setting
+  lineinfile:
+    dest: /etc/cloud/cloud.cfg
+    regexp: '^preserve_hostname:'
+    line: 'preserve_hostname: true'
+    state: present
+  when: cloud_cfg.stat.exists
+
 - name: Add hostname to /etc/hosts
   lineinfile:
     dest: /etc/hosts

site.yml

@@ -8,6 +8,7 @@
         cache_valid_time: 3600
   roles:
     - role: instance
+      tags: instance
     - role: apt
     - role: firewall
     - role: administrators