As far as I know, WARP is not the preferred connector in a production situation, least of all in a multi-tomcat scenario, for various reasons. Mod_jk supports everything you need out of the box, and JK2 (mod_jk2) is actively developed. I don't think WARP is actively developed any longer, though I could be wrong. In any case, it never got past beta stage, even though it seems to be stable enough to work in some situations.
John > -----Original Message----- > From: Matt Raible [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, September 25, 2002 6:36 PM > To: 'Tomcat Users List' > Cc: 'Keith Glen Bjorndahl' > Subject: Apache 2.x and Tomcat 4.x - AJP or mod_webapp > > > I'm trying to create different instances of Tomcat similar to what my > ISP has. I think they have an Apache front-end and each user > gets their > own instance of Tomcat and JVM. I want to setup this same thing for a > client I have - and I *hope* to make it run on OS X, Windows (2000/XP) > and Linux (Red Hat 7.3). Linux is their production platform. > > I read this article (http://www.ubeans.com/tomcat/) which > details how to > do it with the AJP connector. I think I read that the WARP > connector is > not supported on Windows - is this true? What do you veterans > recommend? We've got a fresh server and our application works across > all 4.x versions of Tomcat, so I'd like to use the latest stuff. > > Some interesting stuff from the article: > ---------------------------------------- > Question 1: > Why did you choose to use the AJP13 connector rather than the WARP > connector that is recommended? > > Answer: > The warp connector is used in conjunction with mod_webapp, and > mod_webapp does not currently support load balancing. > > Also, I found the documentation for the warp connector on the Jakarta > web site to be quite lacking. See: > http://jakarta.apache.org/tomcat/tomcat-4.0-doc/config/warp.html > > I know that the future lies in the warp connector, but in the > meantime, > I needed something. The documentation did not explain to me > exactly what > benefits I would get from using the Warp connector as opposed > to AJP13. > > Question 2: > You might specify that creating two instances of the tomcat > installation > is not needed as you can share the main binaries and libs by > specifying > 2 distinct CATALINA_BASE variables. > > True, but in real life the two tomcat servers are usually > located on two > different machines. My setup might be overkill for a single machine > setup, but it's easy to tar up the "tomcat2" server and put it on a > second machine; you just have to change "localhost" to the appropriate > machine name in /usr/local/apache/conf/workers.properties and you're > done. > > Question 3: > What does not work and what does work in load balancing? > > Answer: > Load balancing works great. > > 1. Session affinity works > Which means that when a client browser is directed to a > Tomcat server by > the load balancer, then future queries from that same browser session > will always be directed to the same tomcat server. This is important > because sessions that are created in a specific tomcat server, say > "tomcat1", do not exist in the other server "tomcat2", and thus if the > client was directed to another tomcat server than the one where his > session is stored, then all his session data would be lost. > > Some people are working on sessions that will be replicated across all > tomcat servers in the cluster, so I'll just wait for it to become > available rather than make a homebrewed distributed session > mechanism. > > The downside of not having sessions replicated across all the tomcat > servers in the cluster is that if one tomcat server dies, all the > sessions that it contained are lost, which usually makes a lot of > unhappy users. > > 2. Failover works > If one tomcat server dies, the load balancer then "rebalances" the > queries to the remaining tomcat servers. > > 3. Failback works > When a tomcat server comes back from the dead, the load balancer > automatically starts to send queries to it. So you can actually add > capacity to your cluster on the fly. > > 4. Weighted load balancing works > In /usr/local/apache/conf/workers.properties, I assigned a load > balancing factor of 100 to both "tomcat1" and "tomcat2" > servers. Then I > changed the lbfactor of "tomcat1" to 101, and I saw that > effectively the > "tomcat1" server received more load than the "tomcat2" > server, which is > something you want when for example your "tomcat1" server is a > faster/newer machine while your "tomcat2" server is a slower machine > which cannnot take as much load as the other one. > > > > -- > To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
