haproxy.conf.in

global
  log 0.0.0.0 local6
  maxconn  ${haproxy-conf:maxconn}
  nbproc 1
#  ulimit-n ${haproxy-conf:ulimit-n}

defaults
  mode http
  option httpclose
  # Remove requests from the queue if people press stop button
  option abortonclose
  # Try to connect this many times on failure
  retries 3
  # If a client is bound to a particular backend but it goes down,
  # send them to a different one
  option redispatch
  monitor-uri /haproxy-ping

  timeout connect 7s
  timeout queue   300s
  timeout client  300s
  timeout server  300s

  # Enable status page at this URL, on the port HAProxy is bound to
  stats enable
  stats uri /haproxy-status
  stats refresh 5s
  stats realm Haproxy statistics

frontend zopecluster
  bind ${haproxy-conf:bind}
  default_backend zope

# Load balancing over the zope instances
backend zope
  # Use Zope's __ac cookie as a basis for session stickiness if present.
  appsession __ac len 32 timeout 1d
  # Otherwise add a cookie called "serverid" for maintaining session stickiness.
  # This cookie lasts until the client's browser closes, and is invisible to Zope.
  cookie serverid insert nocache indirect
  # If no session found, use the roundrobin load-balancing algorithm to pick a backend.
  balance roundrobin
  # Use / (the default) for periodic backend health checks
  option httpchk

  # Server options:
  # "cookie" sets the value of the serverid cookie to be used for the server
  # "maxconn" is how many connections can be sent to the server at once
  # "check" enables health checks
  # "rise 1" means consider Zope up after 1 successful health check
  server  plone0101 127.0.0.1:${ports:instance1} cookie p0101 check maxconn 20 rise 1
  server  plone0102 127.0.0.1:${ports:instance2} cookie p0102 check maxconn 20 rise 1