Troubleshooting

OpenVPN

tun/tap devices

OpenVPN requires a tun device to operate, which may be missing, e.g., if you are running a client inside an LXC container. You may create a tun/tap device with the following commands:

mkdir /dev/net 
mknod /dev/net/tun c 10 200 
chmod 666 /dev/net/tun

You may also need to allow the LXC container to access to devices:

lxc.cgroup.devices.allow = c 10:200 rwm

(See more on https://serverfault.com/questions/429461/no-tun-device-in-lxc-guest-for-openvpn)