In a setup like this where HAProxy1 LBs over N other HAProxies (servers in
a backend of HAProxy1):
HAProxy1
| --> HAProxy2 -> 1 real backend server
| --> HAProxy3 -> 1 real backend server
Is there a way to trigger a retry by HAProxy to use HAProxy3 if it tried
HAProxy2 and just its real backend server was down? i.e. HAProxy1
successfully connected to HAProxy2 but HAProxy2 returned a 503 because its
one backend server was down.
The goal is that the initial call into HAProxy1 succeeds by using the
HAProxy3, even though it tried HAProxy2.
I looked at the 'observe' server option but my read of the config manual is
that it won't trigger a retry (just a failed health check). I also
realize that, in general, retrying on a 503 has idempotency issues so using
a custom 5xx code might be a better signal to indicate no-work was done.
Thanks
