Ask HN: VPN Solution Open Source

I need to implement a VPN in the office that is easy to maintain from the Administration perspective. My company currently has ~50 employees and a standalone ubuntu with openvpn and a single key shared across the whole team, without authentication.

I was looking for some solution with an UI that I could either create/revoke keys, or have a single key + username/password and logs.

Anyone has any recommendations for such a scenario?