# Apply a scaling policy
<a name="endpoint-auto-scaling-add-code-apply"></a>

After you register your model and define a scaling policy, apply the scaling policy to the registered model. This section shows how to apply a scaling policy using the the AWS Command Line Interface (AWS CLI) or the Application Auto Scaling API. 

**Topics**
+ [Apply a target tracking scaling policy (AWS CLI)](#endpoint-auto-scaling-add-code-apply-cli)
+ [Apply a scaling policy (Application Auto Scaling API)](#endpoint-auto-scaling-add-code-apply-api)

## Apply a target tracking scaling policy (AWS CLI)
<a name="endpoint-auto-scaling-add-code-apply-cli"></a>

To apply a scaling policy to your model, use the [put-scaling-policy](https://docs.aws.amazon.com/cli/latest/reference/application-autoscaling/put-scaling-policy.html) AWS CLI command with the following parameters:
+ `--policy-name`—The name of the scaling policy.
+ `--policy-type`—Set this value to `TargetTrackingScaling`.
+ `--resource-id`—The resource identifier for the variant. For this parameter, the resource type is `endpoint` and the unique identifier is the name of the variant. For example, `endpoint/{{my-endpoint}}/variant/{{my-variant}}`.
+ `--service-namespace`—Set this value to `sagemaker`.
+ `--scalable-dimension`—Set this value to `sagemaker:variant:DesiredInstanceCount`.
+ `--target-tracking-scaling-policy-configuration`—The target-tracking scaling policy configuration to use for the model.

**Example**  
The following example applies a target tracking scaling policy named `{{my-scaling-policy}}` to a variant named `{{my-variant}}`, running on the `{{my-endpoint}}` endpoint. For the `--target-tracking-scaling-policy-configuration` option, specify the `config.json` file that you created previously.   

```
aws application-autoscaling put-scaling-policy \
  --policy-name {{my-scaling-policy}} \
  --policy-type TargetTrackingScaling \
  --resource-id endpoint/{{my-endpoint}}/variant/{{my-variant}} \
  --service-namespace sagemaker \
  --scalable-dimension sagemaker:variant:DesiredInstanceCount \
  --target-tracking-scaling-policy-configuration file://config.json
```

## Apply a scaling policy (Application Auto Scaling API)
<a name="endpoint-auto-scaling-add-code-apply-api"></a>

To apply a scaling policy to a variant with the Application Auto Scaling API, use the [PutScalingPolicy](https://docs.aws.amazon.com/autoscaling/application/APIReference/API_PutScalingPolicy.html) Application Auto Scaling API action with the following parameters:
+ `PolicyName`—The name of the scaling policy.
+ `ServiceNamespace`—Set this value to `sagemaker`.
+ `ResourceID`—The resource identifier for the variant. For this parameter, the resource type is `endpoint` and the unique identifier is the name of the variant. For example, `endpoint/{{my-endpoint}}/variant/{{my-variant}}`.
+ `ScalableDimension`—Set this value to `sagemaker:variant:DesiredInstanceCount`.
+ `PolicyType`—Set this value to `TargetTrackingScaling`.
+ `TargetTrackingScalingPolicyConfiguration`—The target-tracking scaling policy configuration to use for the variant.

**Example**  
The following example applies a target tracking scaling policy named `{{my-scaling-policy}}` to a variant named `{{my-variant}}`, running on the `{{my-endpoint}}` endpoint. The policy configuration keeps the average invocations per instance at 70.  

```
POST / HTTP/1.1
Host: application-autoscaling.us-east-2.amazonaws.com
Accept-Encoding: identity
X-Amz-Target: AnyScaleFrontendService.
X-Amz-Date: 20230506T182145Z
User-Agent: aws-cli/2.0.0 Python/3.7.5 Windows/10 botocore/2.0.0dev4
Content-Type: application/x-amz-json-1.1
Authorization: AUTHPARAMS

{
    "PolicyName": "{{my-scaling-policy}}",
    "ServiceNamespace": "sagemaker",
    "ResourceId": "endpoint/{{my-endpoint}}/variant/{{my-variant}}",
    "ScalableDimension": "sagemaker:variant:DesiredInstanceCount",
    "PolicyType": "TargetTrackingScaling",
    "TargetTrackingScalingPolicyConfiguration": {
        "TargetValue": {{70.0}},
        "PredefinedMetricSpecification":
        {
            "PredefinedMetricType": "SageMakerVariantInvocationsPerInstance"
        }
    }
}
```