title: how to overwrite nested default values in Ansible
body: <p>I have some nested default variables in my /defaults/main.yml:</p>
  
  <pre><code>php_fpm_pools:
    - name: www
      user: php-fpm
  </code></pre>
  
  <p>In the playbook, I want to overwrite the user default value, and I tried the following options, to no avail:</p>
  
  <pre><code>roles:
    - {
      name: php-fpm,
  
      php_fpm_pools.[www].user: vagrant
      php_fpm_pools.www.user: vagrant
      php_fpm_pools.['www'].user: vagrant
    }
  </code></pre>
  
  <p>What is the correct syntax that I have to use in order to overwrite that default value?</p>