# PredefinedMetricSpecificationProperty

Contains predefined metric specification information for a target tracking scaling policy for Application Auto Scaling.

`PredefinedMetricSpecification` is a property of the [AWS::ApplicationAutoScaling::ScalingPolicy TargetTrackingScalingPolicyConfiguration](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-applicationautoscaling-scalingpolicy-targettrackingscalingpolicyconfiguration.html) property type.

- Source: Generated code
- Type last changed: v2.93.0 · 23 Aug 2023

## Example

```ts
// The code below shows an example of how to instantiate this type.
// The values are placeholders you should change.
import { aws_applicationautoscaling as appscaling } from 'aws-cdk-lib';
const predefinedMetricSpecificationProperty: appscaling.CfnScalingPolicy.PredefinedMetricSpecificationProperty = {
  predefinedMetricType: 'predefinedMetricType',

  // the properties below are optional
  resourceLabel: 'resourceLabel',
};
```

## Properties

- `predefinedMetricType`: string (required) — The metric type.

  The `ALBRequestCountPerTarget` metric type applies only to Spot fleet requests and ECS services.

- `resourceLabel`: string — Identifies the resource associated with the metric type.

  You can't specify a resource label unless the metric type is `ALBRequestCountPerTarget` and there is a target group attached to the Spot Fleet or ECS service.

  You create the resource label by appending the final portion of the load balancer ARN and the final portion of the target group ARN into a single value, separated by a forward slash (/). The format of the resource label is:

  `app/my-alb/778d41231b141a0f/targetgroup/my-alb-target-group/943f017f100becff` .

  Where:

  - app/<load-balancer-name>/<load-balancer-id> is the final portion of the load balancer ARN
  - targetgroup/<target-group-name>/<target-group-id> is the final portion of the target group ARN.

  To find the ARN for an Application Load Balancer, use the [DescribeLoadBalancers](https://docs.aws.amazon.com/elasticloadbalancing/latest/APIReference/API_DescribeLoadBalancers.html) API operation. To find the ARN for the target group, use the [DescribeTargetGroups](https://docs.aws.amazon.com/elasticloadbalancing/latest/APIReference/API_DescribeTargetGroups.html) API operation.