# TargetTrackingScalingPolicy Extends: Construct › TargetTrackingScalingPolicy Implements: IConstruct, IDependable - Source: [`aws-applicationautoscaling/lib/target-tracking-scaling-policy.ts`](https://github.com/aws/aws-cdk/blob/v2.276.0/packages/aws-cdk-lib/aws-applicationautoscaling/lib/target-tracking-scaling-policy.ts#L122) ## Example ```ts // The code below shows an example of how to instantiate this type. // The values are placeholders you should change. import * as cdk from 'aws-cdk-lib'; import { aws_applicationautoscaling as appscaling } from 'aws-cdk-lib'; import { aws_cloudwatch as cloudwatch } from 'aws-cdk-lib'; import { aws_applicationautoscaling as interfaces_applicationautoscaling } from 'aws-cdk-lib/interfaces'; declare const metric: cloudwatch.Metric; declare const scalableTargetRef: interfaces_applicationautoscaling.IScalableTargetRef; const targetTrackingScalingPolicy = new appscaling.TargetTrackingScalingPolicy(this, 'MyTargetTrackingScalingPolicy', { scalingTarget: scalableTargetRef, targetValue: 123, // the properties below are optional customMetric: metric, disableScaleIn: false, policyName: 'policyName', predefinedMetric: appscaling.PredefinedMetric.APPSTREAM_AVERAGE_CAPACITY_UTILIZATION, resourceLabel: 'resourceLabel', scaleInCooldown: cdk.Duration.minutes(30), scaleOutCooldown: cdk.Duration.minutes(30), }); ``` ## Initializer ```ts new TargetTrackingScalingPolicy(scope: Construct, id: string, props: TargetTrackingScalingPolicyProps) ``` ## Construct Props - `customMetric`: [IMetric](/cdk/api/v2/docs/aws-cdk-lib.aws_cloudwatch.IMetric.html) — A custom metric for application autoscaling. **Default:** No custom metric. The metric must track utilization. Scaling out will happen if the metric is higher than the target value, scaling in will happen in the metric is lower than the target value. The metric must be in the same account and region as the scaling policy. Exactly one of customMetric or predefinedMetric must be specified. - `disableScaleIn`: boolean = false — Indicates whether scale in by the target tracking policy is disabled. If the value is true, scale in is disabled and the target tracking policy won't remove capacity from the scalable resource. Otherwise, scale in is enabled and the target tracking policy can remove capacity from the scalable resource. - `policyName`: string — A name for the scaling policy. **Default:** Automatically generated name. - `predefinedMetric`: [PredefinedMetric](/cdk/api/v2/docs/aws-cdk-lib.aws_applicationautoscaling.PredefinedMetric.html) — A predefined metric for application autoscaling. **Default:** No predefined metrics. The metric must track utilization. Scaling out will happen if the metric is higher than the target value, scaling in will happen in the metric is lower than the target value. Exactly one of customMetric or predefinedMetric must be specified. - `resourceLabel`: string — Identify the resource associated with the metric type. **Default:** No resource label. Only used for predefined metric ALBRequestCountPerTarget. Example value: `app///targetgroup//` - `scaleInCooldown`: [Duration](/cdk/api/v2/docs/aws-cdk-lib.Duration.html) — Period after a scale in activity completes before another scale in activity can start. **Default:** Duration.seconds(300) for the following scalable targets: ECS services, Spot Fleet requests, EMR clusters, AppStream 2.0 fleets, Aurora DB clusters, Amazon SageMaker endpoint variants, Custom resources. For all other scalable targets, the default value is Duration.seconds(0): DynamoDB tables, DynamoDB global secondary indexes, Amazon Comprehend document classification endpoints, Lambda provisioned concurrency - `scaleOutCooldown`: [Duration](/cdk/api/v2/docs/aws-cdk-lib.Duration.html) — Period after a scale out activity completes before another scale out activity can start. **Default:** Duration.seconds(300) for the following scalable targets: ECS services, Spot Fleet requests, EMR clusters, AppStream 2.0 fleets, Aurora DB clusters, Amazon SageMaker endpoint variants, Custom resources. For all other scalable targets, the default value is Duration.seconds(0): DynamoDB tables, DynamoDB global secondary indexes, Amazon Comprehend document classification endpoints, Lambda provisioned concurrency - `scalingTarget`: [IScalableTargetRef](/cdk/api/v2/docs/aws-cdk-lib.interfaces.aws_applicationautoscaling.IScalableTargetRef.html) (required) - `targetValue`: number (required) — The target value for the metric. ## Properties - `node`: [Node](/cdk/api/v2/docs/constructs.Node.html) — The tree node. - `scalingPolicyArn`: string — ARN of the scaling policy. ## Methods - `isConstruct(x: any): boolean` (static) — Checks if `x` is a construct. Use this method instead of `instanceof` to properly detect `Construct` instances, even when the construct library is symlinked. Explanation: in JavaScript, multiple copies of the `constructs` library on disk are seen as independent, completely different libraries. As a consequence, the class `Construct` in each copy of the `constructs` library is seen as a different class, and an instance of one class will not test as `instanceof` the other class. `npm install` will not create installations like this, but users may manually symlink construct libraries together or use a monorepo tool: in those cases, multiple copies of the `constructs` library can be accidentally installed, and `instanceof` will behave unpredictably. It is safest to avoid using `instanceof`, and using this type-testing method instead. **Parameters** - `x` — Any object. **Returns:** true if `x` is an object created from a class which extends `Construct`. - `toString(): string` — Returns a string representation of this construct. - `with(...mixins: IMixin[]): IConstruct` — Applies one or more mixins to this construct. Mixins are applied in order. The list of constructs is captured at the start of the call, so constructs added by a mixin will not be visited. Use multiple `with()` calls if subsequent mixins should apply to added constructs. **Parameters** - `mixins` — The mixins to apply. **Returns:** This construct for chaining