lb_add and lb_remove take a list of dns_names and remove them from ELB

fog_ELB.rb

require 'fog'

ELB = Fog::AWS::ELB.new
COMPUTE = Fog::Compute.new( :provider => 'AWS')

def server_from_dns_name dns_name
  COMPUTE.servers.all.find {|server| server.dns_name == dns_name}
end

def id_from_dns_name dns_name
  (server_from_dns_name dns_name).id
end

def dns_name_to_id servers
  servers.map {|server| id_from_dns_name server}
end

def lb_remove servers
  ELB.deregister_instances_from_load_balancer(dns_name_to_id(servers), "TOMTEST")
end

def lb_add servers
  ELB.register_instances_with_load_balancer(dns_name_to_id(servers), "TOMTEST")
end