This docker image is an all-in-one pritunl/mongodb3/letsencrypt that allows you to run a vpn server for your cloud infrastructure in an easy way:
docker run -d -v /my/mongo/db:/var/lib/mongodb --privileged --net host spantree/pritunl
Then all you need to do is go to https://<url>/ of your cloud server and login using
pritunl / pritunl .
If you want to enable letsencrypt you need to have a dns and the ports 80 and 443 open, you also need as well to add port 17999 (or another of your choice for the pritunl server)