Hello, 2017-07-18 15:48 GMT+02:00 Suvendu Sekhar Mondal <suv3...@gmail.com>:
> Hello Folks, > > I am new to Apache httpd world and wanted to know more about it. :) > > Reason I got interested in this is that, in our case, we are running > multiple Tomcat JVMs under a single Apache cluster. If we shut down > all the JVMs except one, sometime we get 503s. If we increase the > retry interval to 180(from retry=10), problem goes away. That bring me > to this question, how does Apache detects a stopped Tomcat JVM? If I > have a cluster which contains multiple JVMs and some of them are down, > how Apache finds that one out? Somewhere I read, Apache uses a real > request to determine health of a back end JVM. In that case, will that > request failed(with 5xx) if JVM is stopped? Why higher retry value is > making the difference? > > If someone can explain a bit or point me to some doc, that would be > awesome. > > We are using Apache 2.4.10, byrequests LB algorithm, sticky session, > keepalive is on and ttl=300 for all balancer member. > https://httpd.apache.org/docs/2.4/mod/mod_proxy_hcheck.html is surely a good read for your use case. Moreover be really careful with sticky sessions, they have the downside to tie requests to a specific backend altering the work of the LB algorithm. Luca
