0


does anyone knows how to configure the mod proxy balancer method in order to balance on a secondary backend instance only in case of an overflow of simultaneous requests?

More specifically:
I have an Apache + mod proxy balancer which is in front of a primary Tomcat instance (with https connector) which is able to serve only N simultaneous requests, if it receive more requests it crashes or start responding slow.
I prepared another secondary remote tomcat instance which will be used only for the N+1 requests, if there are less than N simultaneous request it should not be used at all.

I would like to tell Apache to balance on the primary Tomcat instance to max N simultaneous requests. The N+1 request must be balanced on the secondary remote Tomcat instance.

I already tried to use:
- status=+H on the secondary member and max=N on the primary member on BalancerMembers settings
- maxThreads=N and acceptCount=N on the primary tomcat HTTPS connector

but it is not working as expected.
If i test a heavy load i can see Apache not forwarding to secondary the N+1 requests, but it is forwarding all of them on the primary.

Anyone may help me?

Thank you very much.

3
  • As I understand it hotstandby is when no other workers are available, that is, until available worker starts failing, hotstandby does not start working until the other is completely unavailable. Problem in this case is the first worker is still available and serving requests, perhaps playing with the backlog allowance in the backend might help. But the case sounds interesting enough to bring it to the users httpd mailing list or even dev I think. It is good if you explain your reasons to set it up like this instead of just balance the load. Jan 23, 2018 at 11:00
  • the reason is that the secondary instance is in a public cloud and i pay a usage fee for it. if it is not needed i want to load at maximum my servers and direct traffic on public cloud if, and only if, it is needed.
    – Francesco
    Jan 23, 2018 at 11:51
  • I was refering to add the reasoning if you post it in the mailing lists, so if you express a much needed functionality which is not there someone may decide to develop for it. Thanks for sharing it here too though. Jan 23, 2018 at 12:35

0

You must log in to answer this question.

Browse other questions tagged .