[Tenzer]

You can also use Nginx for the PROXY protocol, that was added in version 1.5.12. You should just add "proxy_protocol" to your "listen" directive: http://nginx.org/en/docs/http/ngx_http_core_module.html#list....

[jpgvm]

Cool, does it allow you to control the balancing to enforce source-ip -> backend mapping?

This is required due to the nature of Websockets UPGRADE and most semi-stateful Websockets servers.

[Tenzer]

Sure, that's not really related to the protocol used. It's instead handled by the upstream module and the "ip_hash" flag: http://nginx.org/en/docs/http/ngx_http_upstream_module.html#....