Bug 36507

Summary:	mod_proxy_balancer does not handle sticky sessions with tomcat correctly
Product:	Apache httpd-2	Reporter:	Christoph Bachhuber-Haller <bachhube>
Component:	mod_proxy_balancer	Assignee:	Apache HTTPD Bugs Mailing List <bugs>
Status:	RESOLVED FIXED
Severity:	major	CC:	bachhube
Priority:	P2	Keywords:	PatchAvailable
Version:	2.1-HEAD
Target Milestone:	---
Hardware:	Other
OS:	other
Attachments:	Patch against trunk

Description Christoph Bachhuber-Haller 2005-09-05 17:41:35 UTC

Apache Tomcat uses JSESSIONID values like
95C5BB2B084DB06938BF798FCF3B3994.tomcat2 for sticky sessions. "tomcat2" is the
route set in jvmRoute in the Engine element in server.xml. 

I expected that mod_proxy_balancer would match its path argument against the
part after the . from JSESSIONID, but it tries to match against the whole cookie
and fails obviousely. (in httpd-2.1.6-alpha/modules/proxy/mod_proxy_balancer.c,
find_route_worker function)

That way, balancer is useless as a replacement for mod_jk load balancing with
sticky sessions.

Comment 1 Rüdiger Plüm 2005-09-28 23:17:33 UTC

Created attachment 16546 [details]
Patch against trunk

I can confirm this problem.
The attached patch should fix this. Can you please give it a try?

Comment 2 Christoph Bachhuber-Haller 2005-10-04 14:47:58 UTC

Hi Ruediger,

(In reply to comment #1)
> Created an attachment (id=16546) [edit]
> Patch against trunk
> 
> I can confirm this problem.
> The attached patch should fix this. Can you please give it a try?

I can confirm that this patch fixes my problem. Thank you very much! I wonder
though whether the tomcat session id format is any standard or if apache should
support sticky sessions for load balancing in a more generic way. 

Bye,
Christoph

Comment 3 Ruediger Pluem 2005-10-05 10:57:57 UTC

Committed to trunk (r295013)
http://svn.apache.org/viewcvs.cgi/httpd/httpd/trunk/modules/proxy/mod_proxy_balancer.c?rev=295013&r1=279973&r2=295013

Comment 4 Ruediger Pluem 2005-10-06 23:14:45 UTC

Committed and backported to 2.2.x branch (r306888).

Comment 5 Ruediger Pluem 2005-10-06 23:21:00 UTC

> though whether the tomcat session id format is any standard or if apache should
> support sticky sessions for load balancing in a more generic way. 

It does. As you can choose the name of the cookie you can make any application
where you can set a cookie work with that. Just set cookie BLAH=a.route in your
application. Of course it is more convenient if the application container is
able to do this (like Tomcat). BTW: I know no standard for coding such routing
information inside a cookie. But if you know one I would be interested to get it
known.