The article I read did not mention anything about virtual hosts.  My
main problem now is just starting apache, which I've detailed in a
previous e-mail.

Matt

> -----Original Message-----
> From: Scott Jones [mailto:[EMAIL PROTECTED]] 
> Sent: Wednesday, September 25, 2002 7:31 PM
> To: Tomcat Users List
> Cc: Matt Raible
> Subject: Re: Apache 2.x and Tomcat 4.x - AJP or mod_webapp
> 
> 
> Hi Matt,
> 
> I've got mulitple instances of Tomcat running with Apache 
> using AJP (on linux, but should work basically the same on windows).  
> 
> 1.) You need to configure your apache to do virtual hosts 
> (have you done this yet).
> 2.) Set up your workers.properties file (used and read by 
> apache to connect to tomcat using mod_jk) to have several 
> workers.  Then set up your instances of tomcat with different 
> ports in their server.xml configurations (different ports for 
> the shutdown port and for the AJP13 port -- you won't need 
> anything else).
> 
> Cheers,
> 
> Scott
> 
> On Wed, 2002-09-25 at 15:35, Matt Raible wrote:
> > 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.
> > 
> > 
> > 
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