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From weiji <nabbl...@hotmail.com>
Subject RE: [users@httpd] mod_jk load balancing issue: one worker always dies...
Date Thu, 15 Nov 2007 00:02:58 GMT

Update:

I've been double checking various things and I saw that the Apache
documentation recommends to restart the server using a control script, so
I'll use "apachectl -k restart" from now on.

For JBoss to run multiple instances on the same machine, they have a service
binding manager to handle all the various different ports.  I basically
followed the setup available here:
http://wiki.jboss.org/wiki/Wiki.jsp?page=ConfiguringMultipleJBossInstancesOnOneMachine
.

I found that the different port options they have by default (named
"ports-01", "ports-02", and "ports-03") use the same AJP port of 8009, so I
thought this was the cause of the problem.  However, setting the entry for
ports-02 to 8010 does not resolve the issue;  rather it now causes both of
the Apache workers to go into an error state... very strange.

Since this seems to be an issue with JBoss, I'll move the issue over to them
and see if they have any insight.

Thanks,
KaJun



weiji wrote:
> 
> Hi John,
> 
> Yes, I do have the JBoss jvmRoute attribute set up correctly.  
> 
> I also noticed the balance vs balanced wording, and I tested my setup with
> both and there seemed to be no difference.  I assume that both wordings
> are correct because node2 can respond to requests with both.  (And after
> any configuration modification, I do restart Apache with "httpd2 -k
> restart".)
> 
> JBoss also had another configuration setting (thank goodness for taking
> notes during setup).  In
> jboss/server/myapp/deploy/jbossweb-tomcat55.sar/META-INF/jboss-service.xml,
> find the attribute 'name="UseJK"', change value from false to true.
> 
> Thanks,
> KaJun
> 
> 
> 
> 
> 
> John Moore-3 wrote:
>> 
>> Do you have the jvmRoute setup in the server.xml in JBoss/Tomcat (e.g.
>> <Engine ... jvmRoute="node1">) ?
>> 
>> you have balance_workers, I think it's balanced_workers
>> 
>> John
>> 
>> -----Original Message-----
>> From: weiji [mailto:nabbleOp@hotmail.com] 
>> Sent: Tuesday, November 13, 2007 2:21 PM
>> To: users@httpd.apache.org
>> Subject: [users@httpd] mod_jk load balancing issue: one worker always
>> dies...
>> 
>> 
>> Hi,
>> 
>> I'm using mod_jk to load balance two JBoss instances.  However, it seems
>> to
>> always use only one of them.  
>> 
>> From watching the status page, I found that the two workers both come up
>> in
>> an OK state.  However, sending a request through the load balancer seems
>> to
>> always cause the first one to switch to an error state (ERR), causing
>> the
>> request to be routed to the second worker (which successfully returns
>> the
>> requested page).  After the status worker's maintenance countdown, the
>> state
>> of the first worker switches to ERR/REC and then it never gets itself
>> out of
>> that state.  At this point, we can still hit both instances of JBoss by
>> using a direct port to access our webapp.
>> 
>> If I use the reset command on the bad worker, it comes back up as
>> OK/IDLE
>> but sending a request through the balancer will produce the same
>> behavior.
>> 
>> I thought the two JBoss instances might be interfering with each other,
>> so I
>> shut down the second JBoss instance and configured mod_jk to use only
>> node1
>> (set "worker.loadbalancer.balance_workers=node1" only) and restarted
>> Apache,
>> and the worker still goes into an Error state.
>> 
>> Here are the setup details:
>> Suse enterprise linux 10
>> Apache 2.2.0-21.2
>> mod_jk "1.2.25-httpd-2.2.4"
>> 
>> the workers.properties file:
>> 
>> # Define list of workers that will be used
>> # for mapping requests
>> worker.list=loadbalancer,status
>> 
>> # Define Node1
>> # modify the host as your host IP or DNS name.
>> # port is the AJP port defined in server.xml
>> worker.node1.port=8009
>> worker.node1.host=192.168.4.151
>> worker.node1.type=ajp13
>> worker.node1.lbfactor=1
>> #worker.node1.cachesize=10
>> 
>> # Define Node2
>> # modify the host as your host IP or DNS name.
>> # port is the AJP port defined in server.xml
>> worker.node2.port=8010
>> worker.node2.host=192.168.4.151
>> worker.node2.type=ajp13
>> worker.node2.lbfactor=1
>> #worker.node2.cachesize=10
>> 
>> # Load-balancing behaviour
>> worker.loadbalancer.type=lb
>> worker.loadbalancer.balance_workers=node1,node2
>> worker.loadbalancer.sticky_session=1
>> 
>> # Status worker for managing load balancer
>> worker.status.type=status
>> 
>> 
>> 
>> Has anyone seen something like this?  Is there a workaround or some
>> configuration that I need to adjust?
>> 
>> Thanks,
>> KaJun
>> -- 
>> View this message in context:
>> http://www.nabble.com/mod_jk-load-balancing-issue%3A-one-worker-always-d
>> ies...-tf4800991.html#a13736022
>> Sent from the Apache HTTP Server - Users mailing list archive at
>> Nabble.com.
>> 
>> 
>> ---------------------------------------------------------------------
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>> 
>> ---------------------------------------------------------------------
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>> 
>> 
> 
> 

-- 
View this message in context: http://www.nabble.com/mod_jk-load-balancing-issue%3A-one-worker-always-dies...-tf4800991.html#a13759139
Sent from the Apache HTTP Server - Users mailing list archive at Nabble.com.


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