Ubuntu 16.04 has systemd as its init system. Usually getting an OpenVPN client configuration going, is a matter of dropping the .conf or .ovpn file together with key and certs, into /etc/openvpn. On Ubuntu 16.04, you can ‘service openvpn restart’ all you like, but no connection is being initiated, and the logs stay silent.
- edit /etc/default/openvpn, uncomment AUTOSTART=”all”
- sudo systemctl daemon-reload
- sudo service openvpn restart
The comments still say “all” is the default, but that is no longer true in Ubuntu 16.04.
It is also possible to systemd-manage individual server/client configurations, in the style of ‘service openvpn@<my-config> start/stop/status’. See https://fedoraproject.org/wiki/Openvpn#Setting_up_a_Linux_OpenVPN_client.