OpenVPN in a Docker container on a Raspberry Pi

Install Docker on the Pi
Clone the OpenVPN for Docker repository
Enter the docker-openvpn folder
Build the image

docker build -t your-prefix/open-vpn .

Follow the README in the repo or these slightly modified instructions below:

Initialise the data volume

export OVPN_DATA="ovpn-data"
export OVPN_IMAGE="your-prefix/open-vpn"
docker volume create --name ${OVPN_DATA}
docker run -v ${OVPN_DATA}:/etc/openvpn --rm ${OVPN_IMAGE} ovpn_genconfig -u udp://your.server.vpn
docker run -v ${OVPN_DATA}:/etc/openvpn --rm -it ${OVPN_IMAGE} ovpn_initpki
# (this can take a while)

Start the server

docker run -v ${OVPN_DATA}:/etc/openvpn -d -p 1194:1194/udp --cap-add=NET_ADMIN --restart=always ${OVPN_IMAGE}

Generate a client certificate with a passphrase

docker run -v ${OVPN_DATA}:/etc/openvpn --rm -it ${OVPN_IMAGE} easyrsa build-client-full your-client-name

Retrieve the client configuration with embedded certificates for the use within OpenVPN Connect

docker run -v ${OVPN_DATA}:/etc/openvpn --rm ${OVPN_IMAGE} ovpn_getclient your-client-name > your-client-name.ovpn

Fetch the .ovpn file from your server
Archive with the passphrase password

zip -er your-client-name.zip your-client-name.ovpn

Distribute the zip to the 'client' and send the passphrase in a separate channel.