DescribeLoadBalancerTargetGroups - Amazon EC2 Auto Scaling
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This API operation is superseded by DescribeTrafficSources, which can describe multiple traffic sources types. We recommend using DetachTrafficSources to simplify how you manage traffic sources. However, we continue to support DescribeLoadBalancerTargetGroups. You can use both the original DescribeLoadBalancerTargetGroups API operation and DescribeTrafficSources on the same Auto Scaling group.

Gets information about the Elastic Load Balancing target groups for the specified Auto Scaling group.

To determine the attachment status of the target group, use the State element in the response. When you attach a target group to an Auto Scaling group, the initial State value is Adding. The state transitions to Added after all Auto Scaling instances are registered with the target group. If Elastic Load Balancing health checks are enabled for the Auto Scaling group, the state transitions to InService after at least one Auto Scaling instance passes the health check. When the target group is in the InService state, Amazon EC2 Auto Scaling can terminate and replace any instances that are reported as unhealthy. If no registered instances pass the health checks, the target group doesn't enter the InService state.

Target groups also have an InService state if you attach them in the CreateAutoScalingGroup API call. If your target group state is InService, but it is not working properly, check the scaling activities by calling DescribeScalingActivities and take any corrective actions necessary.

For help with failed health checks, see Troubleshooting Amazon EC2 Auto Scaling: Health checks in the Amazon EC2 Auto Scaling User Guide. For more information, see Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group in the Amazon EC2 Auto Scaling User Guide.


You can use this operation to describe target groups that were attached by using AttachLoadBalancerTargetGroups, but not for target groups that were attached by using AttachTrafficSources.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.


The name of the Auto Scaling group.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: Yes


The maximum number of items to return with this call. The default value is 100 and the maximum value is 100.

Type: Integer

Required: No


The token for the next set of items to return. (You received this token from a previous call.)

Type: String

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

Response Elements

The following elements are returned by the service.


Information about the target groups.

Type: Array of LoadBalancerTargetGroupState objects


A string that indicates that the response contains more items than can be returned in a single response. To receive additional items, specify this string for the NextToken value when requesting the next set of items. This value is null when there are no more items to return.

Type: String

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*


For information about the errors that are common to all actions, see Common Errors.


The NextToken value is not valid.

HTTP Status Code: 400


You already have a pending update to an Amazon EC2 Auto Scaling resource (for example, an Auto Scaling group, instance, or load balancer).

HTTP Status Code: 500

See Also

For more information about using this API in one of the language-specific Amazon SDKs, see the following: