Start an OpenVPN Container as a systemd managed service under CoreOS

openvpn.service

[Unit]
Description=OpenVPN
After=docker.service
Requires=docker.service

[Service]
TimeoutStartSec=0
Environment="OVPN_DATA=ovpn-data"
Environment="OVPN_IMAGE=kylemanna/openvpn"
Environment="OVPN_CONTAINER=openvpn_server"
ExecStartPre=-/usr/bin/docker stop ${OVPN_CONTAINER}
ExecStartPre=-/usr/bin/docker rm ${OVPN_CONTAINER}
ExecStartPre=/usr/bin/docker pull ${OVPN_IMAGE}
ExecStart=/usr/bin/docker run --name ${OVPN_CONTAINER} \
	--volumes-from ${OVPN_DATA} -p 1194:1194/udp \
	--cap-add=NET_ADMIN ${OVPN_IMAGE}
ExecStop=/usr/bin/docker stop ${OVPN_CONTAINER}

[Install]
WantedBy=multi-user.target

A data-only container ovpn-data provides the directory /etc/openvpn.