Active Passive Load Balancer Configuration for HAProxy

It took me a while to understand the help for the configuration file for HAProxy, another software load balancer that runs on a number of *nix-based systems. Here’s the resulting file that we used to successfully test an active-passive machine configuration that someone will hopefully find useful one day.

global
    log     127.0.0.1 alert 
    log     127.0.0.1 alert debug
    maxconn 4096

defaults
    log        global
    mode       http
    option     httplog
    option     dontlognull
    option     redispatch
    retries    3
    maxconn    2000
    contimeout 5000
    clitimeout 50000
    srvtimeout 50000

####################################
#
#           loadbalancer
#         10.0.16.222:8555
#           /          \
#   webServerA         webServerB
# 10.0.5.91:8181     10.0.5.92:8181
#    (active)           (passive)
#
####################################

listen webfarm 10.0.16.222:8555
    mode    http
    stats   enable
    balance roundrobin
    option  httpclose
    option  forwardfor
    option  httplog
    option  httpchk    GET /someService/isAlive             
    server  webServerA 10.0.5.91:8181 check inter 5000 downinter 500    # active node
    server  webServerB 10.0.5.92:8181 check inter 5000 backup           # passive node