ansible_facts_fail.yml

---

- hosts: backend
  become: yes
  become_method: sudo

  tasks:
    - name: Facts
      setup:

- hosts: frontend
  become: yes
  become_method: sudo

  pre_tasks:
    - name: Check Facts
      shell: echo " {{ hostvars[item]['ansible_hostname'] }}"
      with_items: "{{groups['backend']}}"

  roles:
    - reverse_proxy
    
    ...