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 vote for it in bugzilla if you also think it's useful. https://issues.apache.org/bugzilla/show_bug.cgi?id=51247 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 kmash...@yahoo.com
