AWS: Use auto-scaling group to run minions

This uses the dynamic CIDR work, and we set source-dest-check to false
when we configure the route (which kind-of makes sense)

pkg/cloudprovider/aws/aws.go

@@ -90,6 +90,8 @@ type EC2 interface {
 	DescribeRouteTables(request *ec2.DescribeRouteTablesInput) ([]*ec2.RouteTable, error)
 	CreateRoute(request *ec2.CreateRouteInput) (*ec2.CreateRouteOutput, error)
 	DeleteRoute(request *ec2.DeleteRouteInput) (*ec2.DeleteRouteOutput, error)
+
+	ModifyInstanceAttribute(request *ec2.ModifyInstanceAttributeInput) (*ec2.ModifyInstanceAttributeOutput, error)
 }
 
 // This is a simple pass-through of the ELB client interface, which allows for testing
@@ -414,6 +416,10 @@ func (s *awsSdkEC2) DeleteRoute(request *ec2.DeleteRouteInput) (*ec2.DeleteRoute
 	return s.ec2.DeleteRoute(request)
 }
 
+func (s *awsSdkEC2) ModifyInstanceAttribute(request *ec2.ModifyInstanceAttributeInput) (*ec2.ModifyInstanceAttributeOutput, error) {
+	return s.ec2.ModifyInstanceAttribute(request)
+}
+
 func init() {
 	cloudprovider.RegisterCloudProvider(ProviderName, func(config io.Reader) (cloudprovider.Interface, error) {
 		creds := credentials.NewChainCredentials(

pkg/cloudprovider/aws/aws_routes.go

@@ -69,9 +69,29 @@ func (s *AWSCloud) ListRoutes(clusterName string) ([]*cloudprovider.Route, error
 	return routes, nil
 }
 
+// Sets the instance attribute "source-dest-check" to the specified value
+func (s *AWSCloud) configureInstanceSourceDestCheck(instanceID string, sourceDestCheck bool) error {
+	request := &ec2.ModifyInstanceAttributeInput{}
+	request.InstanceID = aws.String(instanceID)
+	request.SourceDestCheck = &ec2.AttributeBooleanValue{Value: aws.Boolean(sourceDestCheck)}
+
+	_, err := s.ec2.ModifyInstanceAttribute(request)
+	if err != nil {
+		return fmt.Errorf("error configuring source-dest-check on instance %s: %v", instanceID, err)
+	}
+	return nil
+}
+
 // CreateRoute implements Routes.CreateRoute
 // Create the described route
 func (s *AWSCloud) CreateRoute(clusterName string, nameHint string, route *cloudprovider.Route) error {
+	// In addition to configuring the route itself, we also need to configure the instance to accept that traffic
+	// On AWS, this requires turning source-dest checks off
+	err := s.configureInstanceSourceDestCheck(route.TargetInstance, false)
+	if err != nil {
+		return err
+	}
+
 	table, err := s.findRouteTable(clusterName)
 	if err != nil {
 		return err

pkg/cloudprovider/aws/aws_test.go

@@ -372,6 +372,10 @@ func (s *FakeEC2) DeleteRoute(request *ec2.DeleteRouteInput) (*ec2.DeleteRouteOu
 	panic("Not implemented")
 }
 
+func (s *FakeEC2) ModifyInstanceAttribute(request *ec2.ModifyInstanceAttributeInput) (*ec2.ModifyInstanceAttributeOutput, error) {
+	panic("Not implemented")
+}
+
 type FakeELB struct {
 	aws *FakeAWSServices
 }