This guide quickly describes how to connect a Linux container as VPN client with OpenVPN.

There are some settings on the host's side required, because OpenVPN requires a specific tun interface.

1. Edit the config of the container that should get VPN functionalities

   nano /etc/pve/lxc/<container-id>.conf

2. Add this two lines to the config:

   lxc.cgroup2.devices.allow: c 10:200 rwm
   lxc.mount.entry: /dev/net dev/net none bind,create=dir

3. After saving change the owner of the device:

   chown 100000:100000 /dev/net/tun

4. You can check the permissions with:

   ls -l /dev/net/tun

   It should print:

   crw-rw-rw- 1 100000 100000 10, 200 Dec 22 13:26 /dev/net/tun

5. Finished! You can now start the container and connect to the OpenVPN server

   openvpn --config <config-file>.ovpn

Sourced from pve.proxmox.com - OpenVPN in LXC