[pm7]

I doubt serious VPN provider are using LXC/OpenVZ containers. They don't even work with OpenVPN without special setup from provider, I don't know how about other protocols.

[ju-st]

NordVPN _was_ (and certainly still is) using LXC containers. Look at the document linked in the Techcrunch article.

[tmikaeld]

Both LXC and OpenVZ can run VPN services with just setting a couple of flags, I've done it on both.

[pm7]

I know, but these flags have to be set by provider of container, not user (provider of VPN). And they might require changes in kernel.