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From Jim Jagielski <>
Subject Re: id=51247 Enhance mod_proxy and _balancer with worker status flag to only accept sticky session routes
Date Tue, 24 May 2011 14:18:04 GMT
I like the concept... will review.

PS: Most patches should be against trunk. We fold into trunk,
    test and only then propose for backport for 2.2.x

On May 23, 2011, at 3:10 PM, Keith Mashinter wrote:

> I've added a patch to the proxy/balancer to allow for route-only workers are only enabled
for sticky session routes, allowing for an even more graceful fade-out of a server than making
its lbfactor=1 compared to lbfactor=100 for others.  
> Please reply/vote if you also think it's useful.
> This enhancement, actually SVN Patched against 2.2.19, provides a worker status
> flag to set a proxy worker as only accepting requests with sticky session
> routes, e.g. only accept requests with a .route such as Cookie
> JSESSIONID=xxx.tc2.
> This allows for a graceful fade-out of servers when their sessions are removed;
> they continue to receive requests for their sticky session routes but are
> passed over for requests with no specified route, just as if they were
> disabled.  In other words, route-only workers are only enabled for sticky
> session routes.
> Intended use (Tomcat JSESSIONID noted here but could be PHPSESSIONID, Ruby
> _session_id, or anything with cookie or request-parameter based session ids):
> 1. An Apache rev-proxy running for multiple Tomcats.
> 2. To fade-out a Tomcat for maintenance, set route-only enabled in
>  the
> balancer-manager or reload the configuration with the worker status +R.
> (This depends on Tomcat web-apps delete session cookies, see further below.)
> 3. Check on the balancer-manager or its Tomcat worker even a few minutes /
> hours, and when it seems to have completed old sessions you can mark it fully
> disabled.
> 4. Once done maintenance, you can then set route-only disabled (status -R) and
> fully enable the worker again.
> To delete a JSESSIONID Cookie from a Servlet, you need to specify the same
> Domain and Path as the original Cookie and setMaxAge=0 as in the typical
> example below but you should check on your own Domain and Path when a Cookie is
> created, e.g. watch the Cookie headers in Firefox Firebug.
>     // To delete a Cookie setMaxAge(0) and also any original domain and path if
> specified.
>     Cookie ck = new
>  Cookie("JSESSIONID", null);
>     //ck.setDomain("");
>     ck.setPath(request.getContextPath());
>     ck.setMaxAge(0);
>     response.addCookie(ck);
> \|/- Keith Mashinter 

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