Maybe this should be a admin-configurable solution.
Something like:
Apache proxy checks backend server port 4711 and expects load data in a defined format. And we can configure, how often apache checks this backend server (maybe just every 10 seconds and not with every request...).
And everyone can write its own load-detection script to deliver this data on port 4711 ?
(in my opinion, we should separate application and application server from infrastructure questions. And the load detection is an infrastructure question).
Uli
Von: Daniel Ruggeri [mailto:druggeri@xxxxxxxxxxx]
Gesendet: Donnerstag, 20. November 2014 14:50
An: users@xxxxxxxxxxxxxxxx; Jim Jagielski
Betreff: Re: [users@httpd] Load balancing with load detection on backend servers ?
The guts are all there for this to work on the proxy side. We just need to make a module out of it. The question of header name and what-not can be solved by making it configurable. The real $1,000,000 question is what your backend is and how you can gather load information. This would be trivial to do with a Servlet filter in a J2EE app, but I am not sure about other implementations (my own ignorance rather than it being technically impossible).
--
Daniel Ruggeri
The only real question is how the load value of the backend
systems can be known and then "told" to Apache. I had proposed
awhile ago using some sort of custom HTTP X-header to send that
info.
On Nov 19, 2014, at 3:28 AM, Ulrich.Herbst@xxxxxxxxxxxxx wrote:
Hi all,
I know the load_balancing-policies bybusyness, byrequests, bytraffic and heartbeat.
We have a frontend apache, that acts as forwarding proxy to 8 backend servers.
BUT: We want do route the next request to that backend server with least load.
Is there any apache module, that can do this ?
(We use linux and apache 2.4)
Heartbeat is not usable, because our backends do not run apache, but something else.
Uli
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