setting up proxy peers like HAproxy?

[Florin Andrei]

With HAproxy, if you use multiple proxies you can synchronize their 
states:

https://cbonte.github.io/haproxy-dconv/configuration-1.5.html#3.5

This allows, for example, if you're load balancing based on a header 
value, to make sure all clients sending the same header value will end 
up connecting to the same backend node.

Is something like this doable with Nginx?

-- 
Florin Andrei
http://florin.myip.org/