title: PHP mkdir permissione denied only with a scheduled task
body: <pre><code>$old = umask(0);
  mkdir($_SERVER['DOCUMENT_ROOT'].'/images/'.$ID.'/', 0755, true);
  umask($old);
  </code></pre>
  <p>Running this lines from browser works fine, instead if I run this script via a scheduled task, it gives:</p>
  <blockquote>
  <p>'mkdir(): Permission denied'.</p>
  </blockquote>
  <p>Version Plesk Onyx v17.0.17_build1700161028.14 os_CentOS 7</p>
  <p>OS  CentOS Linux 7.4.1708 (Core)</p>
  <p>nginx   1.11.10-centos7.17102311</p>
  <p>php 5.4.16-43.el7_4</p>