Le Sunday 14 August 2011 13:31:57, Ran S a écrit :
> Hi Cyril,
>
> I see, thanks for that.
> So, will the correct way be to configure two different backends and include
> the reqrep for each one of them.
> But how will I get the listen or frontend node to load balance between two
> different backend nodes? I can't find the configuration to do that... is it
> possible?
Well, haproxy is not designed to load balance between backends, but there are
several workarounds (some of them are less elegant than the others).
For your issue, I don't know all about your configuration so maybe it won't
work, but first, can you check if you can unconditionally replace the Host
header with 127.0.0.1 ? Maybe that could do the trick.
reqrep ^Host:\ 172.31.0.103 Host:\ 127.0.0.1
One other workaround is to decide to not load balance but switch to a second
backend under certain conditions (for example when the first backend exceeds a
# of connections).
frontend http-in
bind :80
mode http
option httpclose
use_backend backend2 if { be_conn(backend1) gt 100 }
default_backend backend1
backend backend1
mode http
reqrep ^Host:\ 172.31.0.103 Host:\ 172.31.0.104
server node1 172.31.0.104:85
backend backend2
mode http
reqrep ^Host:\ 172.31.0.103 Host:\ 172.31.0.118
server node2 172.31.0.118:85
Another solution is to add a second level of proxies in haproxy :
listen http-in
bind :80
mode http
option httpclose
server pnode1 127.0.0.1:8104
server pnode2 127.0.0.1:8118
listen proxy104
bind 127.0.0.1:8104
mode http
option httpclose
reqrep ^Host:\ 172.31.0.103 Host:\ 172.31.0.104
server node1 172.31.0.104:85
listen proxy118
bind 127.0.0.1:8118
mode http
option httpclose
reqrep ^Host:\ 172.31.0.103 Host:\ 172.31.0.118
server node2 172.31.0.118:85
This is just some ideas (not tested), or you can try to add some conditions
directly in your apache configuration.
Hope this helps.
--
Cyril Bonté
