====== Ansible installation ======
  * install ''virtualenv''
  * create virtualenv
<code>$ virtualenv ~/VIRTUALENV/ansible2</code>
  * switch to created virtualenv
<code>$ source ~/VIRTUALENV/ansible2/bin/activate</code>
  * upgrade ''setuptools''
<code>$ (ansible2)$ pip install --upgrade setuptools</code>
  * install ansible
<code>$ (ansible2)$ pip install ansible==2.3.1</code>
  * upgrade ansible
<code>$ (ansible2)$ pip install --upgrade ansible==2.3.1</code>