We host multiple apps, on different app servers. What we have is
HAProxy -> App Servers
The App servers can be anything from PHP on Apache to Java app in glassfish. So we use haproxy to expose 1 IP and 1 port to the internet and then also load balance the various app servers, each project get's two app servers, and those two get's balanced against each other.
What we want to do now is, put Varnish infront of HAProxy to cache all traffic, and return it, before it hits HAproxy and get's routed to whatever app server.
Problem is I get a 503 from varnish to haproxy, but if I point varnish to one of the app servers directly it works perfectly. Anyone have any ideas?