I installed privateinternetaccess (PIA) on ubuntu 14.04 using the install_ubuntu.sh script, it was taken from here . VPN servers appeared in network-managere, all is well. Everything works without problems. 
Configured eth0 network interface so that VPN automatically connected. 
But here's the problem, after some system reboot, for some reason it (the eth0 network interface) does not automatically turn on. It is necessary to turn on manually with a mouse. 
Could you tell me what could be the source of the problem? Why eth0 network interface does not automatically connect after system start?