Mailing-List: contact users-help@tomcat.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Tomcat Users List" <users@tomcat.apache.org>
Received-SPF: pass (athena.apache.org: local policy)
Message-ID: <493701D7.3060807@kippdata.de>
Date: Wed, 03 Dec 2008 23:01:59 +0100
From: Rainer Jung <rainer.jung@kippdata.de>
User-Agent: Thunderbird 2.0.0.18 (Windows/20081105)
MIME-Version: 1.0
To: Tomcat Users List <users@tomcat.apache.org>
Subject: Re: can mod_jk detect web service unavailable
References: <3623382.436751228298810598.JavaMail.coremail@bj163app128.163.com>
In-Reply-To: 
 <3623382.436751228298810598.JavaMail.coremail@bj163app128.163.com>
Content-Type: text/plain; charset=x-gbk
Content-Transfer-Encoding: 7bit

Zeke schrieb:
> Hi: I have a JBOSS cluster which use Apache with mod_jk as HTTP load
> balancer. In my cluster, some nodes are deployed web service, but not
> all. For example, node 1 contains web servicebook_service, I can call
> the web service using URL "http://www.node1.com/book_service", but
> node 2 does not contain it. I hope mod_jk can help me to detect
> whether the requested web service exists. That is to say, if I call
> the web service using "http://www.loadbalancer.com/book_service",
> mod_jk can know only node 1 contains the web service and node 2 not,
> then the request will always be dispatched to node 1. But with my
> current configuration on mod_jk and Apache, I fount that the request
> can be dispatched to node 2. Then surely exception will be thrown,
> since the web service not exists on node 2. Can mod_jk support it? Do
> I need some specific configuration? Any suggestion from you will be
> very appreciated!

If that would be an error situation and you want mod_jk to detect that,
then look at fail_on_status in the documentation at:

http://tomcat.apache.org/connectors-doc/reference/workers.html

(and use negative codes).

If this is how you regularly deploy your apps, you should thin twice, if
the idea is good.

You can:

- use several load balancers, each with a different (maybe overlapping)
set of balanced workers (e.g. one for book_service etc.). To get the
stickyness right, you would then need to set the "route" attribute of
the balancer embers.

- use one load balancer and use mapping extensions to configure some
nodes stopped for individual mounts. See

http://tomcat.apache.org/connectors-doc/reference/uriworkermap.html#Rule%20extensions

Regards,

Rainer

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org