loop through each instance, wait for a new one to come up, then deregister and terminate the old one

lib/aws-missing-tools/aws-ha-release/aws-ha-release.rb

@@ -12,6 +12,7 @@ class AwsHaRelease
     end
 
     @max_size_change = 0
+    @inservice_polling_time = 10
   end
 
   def execute!
@@ -23,6 +24,30 @@ class AwsHaRelease
     end
 
     @group.update(desired_capacity: @group.desired_capacity + 1)
+
+    @group.ec2_instances.each do |instance|
+      until all_instances_inservice?(@group.load_balancers)
+        sleep @inservice_polling_time
+      end
+
+      deregister_instance instance, @group.load_balancers
+      sleep opts[:elb_timeout]
+      instance.terminate false
+    end
+
+    @group.update(desired_capacity: @group.desired_capacity - 1)
+
+    if @max_size_change > 0
+      @group.update(max_size: @group.max_size - @max_size_change)
+    end
+
+    @group.resume_all_processes
+  end
+
+  def deregister_instance(instance, load_balancers)
+    load_balancers.each do |load_balancer|
+      load_balancer.instances.deregister instance
+    end
   end
 
   def instances_inservice?(load_balancer)

spec/aws-missing-tools/aws-ha-release/aws-ha-release_spec.rb

@@ -13,7 +13,6 @@ describe 'aws-ha-release' do
   let(:as) { AWS::FakeAutoScaling.new }
 
   before do
-    AWS.stub(:config)
     AWS::AutoScaling.stub(:new).and_return(as)
   end
 
@@ -101,4 +100,30 @@ describe 'aws-ha-release' do
       end
     end
   end
+
+  describe '#deregister_instance' do
+    before do
+      @group = as.groups.create opts[:as_group_name]
+      @aws_ha_release = AwsHaRelease.new(opts)
+    end
+
+    it 'deregisters an instance across all load balancers' do
+      instance_one = AWS::FakeEC2::Instance.new
+      instance_two = AWS::FakeEC2::Instance.new
+
+      elb_one = AWS::FakeELB::LoadBalancer.new 'test_load_balancer_01'
+      elb_two = AWS::FakeELB::LoadBalancer.new 'test_load_balancer_02'
+
+      elb_one.instances.register instance_one
+      elb_one.instances.register instance_two
+
+      elb_two.instances.register instance_one
+      elb_two.instances.register instance_two
+
+      @aws_ha_release.deregister_instance instance_one, [elb_one, elb_two]
+
+      expect(elb_one.instances).not_to include instance_one
+      expect(elb_two.instances).not_to include instance_one
+    end
+  end
 end

spec/spec_helper.rb

@@ -5,4 +5,8 @@ Dir['spec/support/**/*.rb'].each { |f| require File.expand_path(f) }
 
 RSpec.configure do |config|
   config.order = 'random'
+
+  config.before do
+    AWS.stub!
+  end
 end

spec/support/fake_auto_scaling.rb

@@ -42,6 +42,10 @@ module AWS
           self.instance_variable_set "@#{key}", value
         end
       end
+
+      def ec2_instances
+        []
+      end
     end
   end
 end

spec/support/fake_elb.rb

@@ -12,10 +12,20 @@ module AWS
       end
     end
 
-    class InstanceCollection
+    class InstanceCollection < Array
       def initialize
       end
 
+      def register(*instances)
+        self.concat instances
+      end
+
+      def deregister(*instances)
+        instances.each do |i|
+          self.delete i
+        end
+      end
+
       def health
         @health ||= [
           {