Simple TCP with backup config

Hi,

I am doing some intial testing with HAProxy and have come across a problem I don't seem to be able to resolve.

A summary of what I am initially trying to achieve follows. I am trying to use HAProxy to provide a VIP that passes on a tcp (SMTP as it happens) stream to a backend server. If that server is down, I would like the connection forwarded to a backup server.

Doing some testing and watching the status page reveals that if both servers are configured as normal, rather than backup, servers the tcp connection is rerouted when the initial attempt to connect fails. However, when one server is configured as backup, the connection never gets to the backup server.

The config I am using is:
global

        log 127.0.0.1   local0
        log 127.0.0.1   local1 notice
        maxconn 4096
        pidfile /var/run/haproxy.pid


        ##chroot /usr/share/haproxy

        user haproxy
        group haproxy
        daemon


        #debug

        #quiet

        spread-checks 10

defaults default_settings
        log     global
        mode    http
        option  httplog
        option  dontlognull
        option  abortonclose
##      option  allbackups
        option  clitcpka
        option  srvtcpka
        option  forwardfor
        retries 10
        option  redispatch
        maxconn 2000
        backlog 256
        timeout connect 5000
        timeout client 50000
        timeout server 10000

listen www-health
        bind 0.0.0.0:8080
        mode http
        monitor-uri /haproxy
        stats enable
        stats uri /stats

listen smtp
        log global
        bind 0.0.0.0:25
        mode tcp


        #option smtpchk HELO haproxy.local

        option tcplog
        balance roundrobin
        rate-limit sessions 10
        timeout connect 10000
        timeout client 60000
        timeout server 60000

        server smtp01 10.1.1.5:25
        server smtp02 10.1.1.6:25 backup

Note that I am trying to avoid using active health checks and am hoping that the tcp connection failure when connecting to the primary will fall back to the backup server. This works as expected when both servers are configured as "active" rather than "backup" servers. Looking at the status page when one is down, the 10 retries against the "down" server are shown and then the tcp connection succeeds to the second server.

Is this a bug that the tcp connection is not forwarded to the backup server, or am I missing some "obvious" configuration settings?

Many thanks,
Mike Received on 2009/04/17 17:47