fix(pb): makes hostname validation strict enough

playbooks/deploy_and_set_up_lxc_on_proxmox.yaml

@@ -43,8 +43,14 @@
       ansible.builtin.fail:
         msg: |
           Invalid hostname: "{{ lxc_hostname }}"
-          Hostname may only contain letters (a-z, A-Z), numbers (0-9), and hyphens (-).
-      when: not lxc_hostname is regex('^[a-zA-Z0-9-]+$')
+          Hostname must:
+            - contain only letters (a-z, A-Z), digits (0-9), hyphens (-), and dots (.)
+            - not start or end with a hyphen or dot
+            - have each label between 1 and 63 characters
+            - not exceed 253 characters in total
+      when: >
+        lxc_hostname | length > 253 or
+        lxc_hostname is not regex('^[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$')
       run_once: true
 
     - name: Validate IP address

playbooks/deploy_vm_from_cloud_init.yaml

@@ -40,9 +40,15 @@
     - name: Validate hostname
       ansible.builtin.fail:
         msg: |
-          Invalid hostname: "{{ vm_hostname }}"
-          Hostname may only contain letters (a-z, A-Z), numbers (0-9), and hyphens (-).
-      when: not vm_hostname is regex('^[a-zA-Z0-9-]+$')
+          Invalid hostname: "{{ lxc_hostname }}"
+          Hostname must:
+            - contain only letters (a-z, A-Z), digits (0-9), hyphens (-), and dots (.)
+            - not start or end with a hyphen or dot
+            - have each label between 1 and 63 characters
+            - not exceed 253 characters in total
+      when: >
+        lxc_hostname | length > 253 or
+        lxc_hostname is not regex('^[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$')
       run_once: true
 
     - name: Validate IP address