I have a web application deployed on multiple app servers on multiplehost . app1 on host 1,app2 on host 2 etc and each app has 2 jvms say jvm1 ,jvm2

So when a request comes in it could land on say app2jvm1 and we set a cookie called session=app2jvm1.

I want to exercise say "http://URL/myapp/hello.jsp" but exercise each jvm by changing the cookie variable for each request .

What is the best tool for this ?