[edit] Redirecting 51% of the traffic to another URL

http {
    split_clients "${remote_addr}" $redirectSite {
	    51% "1";
	    49% "0";
	}
 
    server {
        location / {
            if ($redirectSite = "1") {
                return 302 "http://www.website2.com/";
            }
            [...]
        }
    }

Module: HttpSplitClientsModule