add: fail gracefully when no ready

ansible/proxmox/update_proxmox.yml

@@ -40,6 +40,9 @@
           run_once: true
           when: ntfy_url is defined
 
+        - ansible.builtin.fail:
+            msg: "Update aborted"
+
 
 - name: Rolling update of Proxmox VE cluster
   hosts: nodes