You don't need to do it their way. You can use a ufw firewall to force traffic over the VPN. If the VPN drops, so does your connection as it won't allow anything out that isn't over tun0.
Assuming you are already connected to the vpn:
sudo eopkg it ufw
Default rules are allow all outgoing, deny all incoming. We want to force all traffic over the VPN. So we need to change the default rules for outgoing:
sudo ufw default deny outgoing
Now we need to allow the the connection to the VPN to be established. If you connect to the same server all the time this is easy with PIA. They provide openvpn-ip config files. If I wanted to connect to their AU Sydney server for example it would look like this.
sudo ufw allow out to 137.59.252.133 port 1198 proto udp
Force traffic over the VPN:
sudo ufw allow out on tun0
We haven't enabled the firewall yet, if you run this command and you're shelled into this system remotely, you will be disconnected and unable to reconnect:
sudo ufw enable
If your VPN provider doesn't provide connection IP's for their server and instead its a hostname. Or you connect to many different locations and don't want to add all those addresses. You should be able to just do this instead of adding the specific server IP(s):
sudo ufw disable- Establish connection to the VPN.
sudo ufw enable
