HAProxy basic example

config.ru

# Simple web server
# Use N_ envvar to identify the process

run lambda {|env|
  [ 200, {}, "Ok @ #{ENV["N_"]}"]
}

haproxy.conf

global
  maxconn 4096
  #user haproxy
  #group haproxy
  #daemon

defaults
  log     global
  mode    http
  option  httplog
  option  dontlognull
  retries 3
  option  redispatch
  maxconn 1

  contimeout      5000
  clitimeout      50000
  srvtimeout      50000

  stats   enable
  stats   auth us3r:passw0rd

frontend graphene
  mode    http
  bind    *:8080

  acl is_api hdr_beg(Host) api.
  acl workper_path path_beg /nodes
  acl accountmanager_path path_beg /account

  use_backend worker if workper_path is_api
  use_backend accountmanager if accountmanager_path is_api

  default_backend webpage

backend webpage
  server webpage1 localhost:8081 check

backend worker
  server webpage1 localhost:8082 check

backend accountmanager
  server accountmanager1 localhost:8083 check

tests

$ curl -H "Host: api.graph" -i localhost:8080/account/0
$ curl -H "Host: api.graph" -i localhost:8080/nodes/0
$ curl -i localhost:8080/nodes/0
$ curl -i localhost:8080