title: Ansible vars_prompt for roles
body: <p>I have a set of <code>Ansible</code> playbooks and the main yml file is like this</p>
  
  <pre><code>- hosts: all 
    roles:
      - common
      - install_nginx
  </code></pre>
  
  <p>I want to add the confirm message when I trigger the playbook. I tried this and did not work</p>
  
  <pre><code>- hosts: all
    vars_prompt:
      - name: CONFIRM
        prompt: Just to confirm you will install stuff
    tasks:
      - fail: no deployment this time
        when: CONFIRM != 'yes'
    roles:
      - common
      - install_nginx
  </code></pre>
  
  <p>How can I use <code>vars_prompt</code> in this case without modify every <code>role</code>?</p>