Well, the title says all. I have no success trying to route docker's network traffic through an active VPN connection (openconnect) or SSH tunnel (sshuttle). Docker creates a virtual network interface called
docker which seems to be ignoring all the iptables rules that sshuttle adds. In VPN case however the entire docker process disconnects while OS's traffic is being routed through VPN.
Please note that I am not trying to push a contained behind VPN. The problem occurs specifically on build stage.