How to disable sticky sessions in Openshift3

Question

If you scale up a Pod in Openshift3, all requests coming from the same client IP address are sent to container which has the session associated.

Is there any configuration to disable sticky sessions? How can I manage the options of internal HAProxy in Openshift?

Answer 1

For posterity, and since I had the same problem, I want to document the solution I used from Graham Dumpleton's excellent comment.

As it turns out, a cookie is set during the first request that redirects subsequent requests to the same back-end. To disable this behavior on a per-route basis:

oc annotate routes myroute haproxy.router.openshift.io/disable_cookies='true'

This prevents the cookie from being set and allows the balance algorithm to select the appropriate back-end for subsequent requests from the same client. To change the balance algorithm:

oc annotate routes myroute haproxy.router.openshift.io/balance='roundrobin'

With these two annotations set, requests from the same client IP address are sent to each back-end in turn, instead of the same back-end over and over.