Maintenance mode on aws elb

aws-elb-maintenance.rb

#!/usr/bin/env ruby

#
# Run with:
#   aws-elb-maintenance on   
# or 
#   aws-elb-maintenance off

require 'rubygems'
require 'aws'

ON_MAIN_PORT  = 81 # on  maintanence (site is NOT running)
OFF_MAIN_PORT = 80 # off maintanence (site IS running)
ELB_NAME      = 'your_elb_name'
ELB_CERT      = 'arn:aws:iam::226094241980:server-certificate/your_cert_name'

if ARGV[0] == 'on'   #go on maintanence mode (site is NOT running)
  elb = AWS::ELB.new.load_balancers[ELB_NAME]
  elb.listeners.each {|l| l.delete }

  elb.listeners.create({
    port: 443, protocol: :https, instance_port: ON_MAIN_PORT, instance_protocol: :http,
    server_certificate: ELB_CERT
  })

  elb.listeners.create({
    port: 80, protocol: :http, instance_port: ON_MAIN_PORT, instance_protocol: :http
  })
end

if ARGV[0] == 'off'  #go off maintanence mode (site is running)
  elb = AWS::ELB.new.load_balancers[ELB_NAME]
  elb.listeners.each {|l| l.delete }

  elb.listeners.create({
    port: 443, protocol: :https, instance_port: OFF_MAIN_PORT, instance_protocol: :http,
    server_certificate: ELB_CERT
  })

  elb.listeners.create({
    port: 80, protocol: :http, instance_port: OFF_MAIN_PORT, instance_protocol: :http
  })
end

nginx.conf

http {
  server {
    
    listen 80 default deferred;
    listen 81 default deferred;
    
    if ($server_port = 81) {
      return 503;
    }
    
  }
}