Now we are using apache2 as frontend, and tomcat as backend. We are using mod_proxy_balancer and AJP. Also we are using stickysession by JSESSIONID cookie:

<Proxy balancer://backend>
     BalancerMember ajp://127.0.0.1:8008 min=10 max=100 ping=5 connectiontimeout=40 ttl=60   retry=20 route=node-1
     BalancerMember ajp://127.0.0.1:8009 min=10 max=100 ping=5 connectiontimeout=40 ttl=60 retry=20 route=node-2
     ProxySet lbmethod=byrequests timeout=30
     ProxySet stickysession=JSESSIONID|jsessionid nofailover=Off
</Proxy>

and using jvmRoute parameter in web.xml to add tail to JSESSIONID cookie:

<Engine name="Catalina" defaultHost="localhost" jvmRoute="node-1">

So far i did not found way to do this in nginx. Is there any solution for this? We are not using session replication, so getting sequential requests to same backend is crucial.