sticky session with apache web server and tomcat servers

Question

I am using apache web server as a load balancer for two tomcat instances behind apache. When the first request goes to node A and second request from the same client goes to node B, i cant access session variables within node A. It's obvious. I surfed in the internet and found that enabling sticky sessions would help. But all the tutorials for enabling the sticky sessions in apache look confusing. Is there any simple step-by-step tutorial for this? Please help.

Code fragment from comment:

ProxyPass /balancer-manager ! 
ProxyPass /balancer://mycluster/ stickysession=JSESSIONID 
ProxyPassReverse /balancer://mycluster/ 
<Proxy balancer://mycluster>; 
  BalancerMember ajp://localhost:9001/ route=NodeA1000 retry=10 
  BalancerMember ajp://localhost:9002/ route=NodeB1000 retry=10 
</Proxy> 

Answer 1

This worked for me...

Instead of using stickysession=JSESSIONID in ProxyPass directive it has to be set within balancer configuration using ProxySet stickysession=JSESSIONID:

<Proxy balancer://mybalancer>
BalancerMember ajp://server1:8009 route=tomcat1
BalancerMember ajp://server2:8009 route=tomcat2
ProxySet lbmethod=bytraffic
ProxySet stickysession=JSESSIONID
</Proxy>
ProxyPass /myapp/ mybalancer://myapp/

It was not working for me when I was using it in ProxyPass as shown below:

ProxyPass /myapp/ mybalancer://myapp/ stickysession=JSESSIONID

This should be added to apache docs, because it's such a pain to solve.

Answer 2

For apache httpd to keep your sessions tied to the same backend, it needs to know which cookie keeps the session ID. For java, this is (usually) JSESSIONID.

If you're using the ProxyPass directive, use

ProxyPass /example http://backend.example.com stickysession=JSESSIONID

To be found in the excellent apache httpd documentation.