Hi DoryZI
You can’t create a tun/tap driver on lxc, Circleci made a blog post [1] explaining this. Nevertheless I create a proxy socks [2] to redirect all traffic to my internal network and solved this vpn problem.
[1] https://circleci.com/blog/vpns-and-why-they-don-t-work/
[2] https://gist.github.com/gianrubio/dce37ee9b9c024937832d776597e2603