Alpine docker image with openvpn for pia (https://www.privateinternetaccess.com) and iptable rules to enforce VPN usage.
docker run -i -t --privileged --dns=209.222.18.222 --dns=209.222.18.218 \
-e PIA_USER='YOUR_PIA_USER' \
-e PIA_PASSWORD='YOUR_PIA_PASSWORD' \
-e PIA_REGION='Switzerland' \
u6f6o/ovpn-pia:latest