gistfile1.rb

# this works:
ruby_block "register_with_elb" do
  require 'AWS'
  ec2 = AWS::ELB::Base.new(:access_key_id => "xxxxxx", :secret_access_key => "yyyy")
  block do
    ec2.register_instances_with_load_balancer(:load_balancer_name => "integration-svnetwork-app", :instances => ["#{@node[:ec2][:instance_id]}"] ) 
  end 
  not_if registered_with_load_balancer?(:ec2 => ec2).to_s
end

# this doesn't:
ruby_block "register_with_elb" do
  require 'AWS'
  ec2 = AWS::ELB::Base.new(:access_key_id => "xxxxxx", :secret_access_key => "yyyy")
  block do
    ec2.register_instances_with_load_balancer(:load_balancer_name => "integration-svnetwork-app", :instances => ["#{@node[:ec2][:instance_id]}"] ) 
  end 
  not_if registered_with_load_balancer?(:ec2 => ec2) 
end