<note> <p>This API operation is superseded by <a>AttachTrafficSources</a>, which can attach multiple traffic sources types. We recommend using <code>AttachTrafficSources</code> to simplify how you manage traffic sources. However, we continue to support <code>AttachLoadBalancerTargetGroups</code>. You can use both the original <code>AttachLoadBalancerTargetGroups</code> API operation and <code>AttachTrafficSources</code> on the same Auto Scaling group.</p> </note> <p>Attaches one or more target groups to the specified Auto Scaling group.</p> <p>This operation is used with the following load balancer types: </p> <ul> <li> <p>Application Load Balancer - Operates at the application layer (layer 7) and supports HTTP and HTTPS. </p> </li> <li> <p>Network Load Balancer - Operates at the transport layer (layer 4) and supports TCP, TLS, and UDP. </p> </li> <li> <p>Gateway Load Balancer - Operates at the network layer (layer 3).</p> </li> </ul> <p>To describe the target groups for an Auto Scaling group, call the <a>DescribeLoadBalancerTargetGroups</a> API. To detach the target group from the Auto Scaling group, call the <a>DetachLoadBalancerTargetGroups</a> API.</p> <p>This operation is additive and does not detach existing target groups or Classic Load Balancers from the Auto Scaling group.</p> <p>For more information, see <a href="https://docs.aws.amazon.com/autoscaling/ec2/userguide/autoscaling-load-balancer.html">Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group</a> in the <i>Amazon EC2 Auto Scaling User Guide</i>. </p>