haproxy.conf

global
  # maximum number of simultaneous active connections from an upstream web server
  maxconn 500 

  # Logging to syslog facility local0
  # log   127.0.0.1       local0

  # Distribute the health checks with a bit of randomness
  spread-checks 5

  # Uncomment the statement below to turn on verbose logging
  #debug

# Settings in the defaults section apply to all services (unless you change it,
# this configuration defines one service, called rails).
defaults

  # apply log settings from the global section above to services
  log global

  # Proxy incoming traffic as HTTP requests
  mode http

  # Distribute incoming requests between Mongrels by round robin algorythm.
  # Note that because of 'maxconn 1' settings in the listen section, Mongrels 
  # that are busy processing some other request will actually be skipped.
  # So, the actual load-balancing behavior is smarter than simple round robin.
  balance roundrobin

  # Maximum number of simultaneous active connections from an upstream web server 
  # per service
  maxconn 500

  # Log details about HTTP requests
  option httplog

  # Abort request if client closes its output channel while waiting for the 
  # request. HAProxy documentation has a long explanation for this option.
  option abortonclose

  # Check if a "Connection: close" header is already set in each direction,
  # and will add one if missing.
  option httpclose

  # If sending a request to one Mongrel fails, try to send it to another, 3 times
  # before aborting the request
  retries 3

  # Do not enforce session affinity (i.e., an HTTP session can be served by 
  # any Mongrel, not just the one that started the session
  option redispatch

  # Timeout a request if the client did not read any data for 120 seconds
  timeout client 120000

  # Timeout a request if Mongrel does not accept a connection for 120 seconds
  timeout connect 120000

  # Timeout a request if Mongrel does not accept the data on the connection,
  # or does not send a response back in 120 seconds
  timeout server 120000
  
  # Remove the server from the farm gracefully if the health check URI returns
  # a 404. This is useful for rolling restarts.
  http-check disable-on-404

  # Enable the statistics page 
  stats enable
  stats uri     /haproxy?stats
  stats realm   Haproxy\ Statistics
  stats auth    haproxy:stats

  # Create a monitorable URI which returns a 200 if haproxy is up
  monitor-uri /haproxy?monitor

  # Specify the HTTP method and URI to check to ensure the server is alive.
  # see http://github.com/jnewland/pulse
  #option httpchk GET /pulse

  # Amount of time after which a health check is considered to have timed out
  timeout check 2000

# Rails service section.
listen rails :8000
  server rails-1 localhost:8001 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-2 localhost:8002 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-3 localhost:8003 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-4 localhost:8004 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-5 localhost:8005 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-6 localhost:8006 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-7 localhost:8007 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-8 localhost:8008 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-9 localhost:8009 maxconn 1 check inter 20000 fastinter 1000 fall 1
  server rails-10 localhost:8010 maxconn 1 check inter 20000 fastinter 1000 fall 1