# Applying a scaling policy


After registering your cluster with ElastiCache for Valkey and Redis OSS auto scaling and defining a scaling policy, you apply the scaling policy to the registered cluster. To apply a scaling policy to an ElastiCache for Redis OSS cluster, you can use the AWS CLI or the Application Auto Scaling API. 

## Applying a scaling policy using the AWS CLI


To apply a scaling policy to your ElastiCache for Valkey and Redis OSS cluster, use the [put-scaling-policy](https://docs.aws.amazon.com/cli/latest/reference/application-autoscaling/put-scaling-policy.html) 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 this parameter, the resource type is `ReplicationGroup` and the unique identifier is the name of the cluster, for example `replication-group/myscalablecluster`. 
+ **--service-namespace** – Set this value to `elasticache`. 
+ **--scalable-dimension** – Set this value to `elasticache:replication-group:NodeGroups`. 
+ **--target-tracking-scaling-policy-configuration** – The target-tracking scaling policy configuration to use for the cluster. 

In the following example, you apply a target-tracking scaling policy named `myscalablepolicy` to an ElastiCache for Valkey and Redis OSS cluster named `myscalablecluster` with ElastiCache auto scaling. To do so, you use a policy configuration saved in a file named `config.json`. 

For Linux, macOS, or Unix:

```
aws application-autoscaling put-scaling-policy \
    --policy-name myscalablepolicy \
    --policy-type TargetTrackingScaling \
    --resource-id replication-group/myscalablecluster \
    --service-namespace elasticache \
    --scalable-dimension elasticache:replication-group:NodeGroups \
    --target-tracking-scaling-policy-configuration file://config.json
```

For Windows:

```
aws application-autoscaling put-scaling-policy ^
    --policy-name myscalablepolicy ^
    --policy-type TargetTrackingScaling ^
    --resource-id replication-group/myscalablecluster ^
    --service-namespace elasticache ^
    --scalable-dimension elasticache:replication-group:NodeGroups ^
    --target-tracking-scaling-policy-configuration file://config.json
```

## Applying a scaling policy using the API


To apply a scaling policy to your ElastiCache for Valkey and Redis OSS cluster, use the [PutScalingPolicy](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. 
+ **--resource-id** – The resource identifier. For this parameter, the resource type is `ReplicationGroup` and the unique identifier is the name of the cluster, for example `replication-group/myscalablecluster`. 
+ **--service-namespace** – Set this value to `elasticache`. 
+ **--scalable-dimension** – Set this value to `elasticache:replication-group:NodeGroups`. 
+ **--target-tracking-scaling-policy-configuration** – The target-tracking scaling policy configuration to use for the cluster. 

In the following example, you apply a target-tracking scaling policy named `myscalablepolicy` to an ElastiCache cluster named `myscalablecluster` with ElastiCache auto scaling. You use a policy configuration based on the `ElastiCachePrimaryEngineCPUUtilization` predefined metric. 

```
POST / HTTP/1.1
Host: autoscaling.us-east-2.amazonaws.com
Accept-Encoding: identity
Content-Length: 219
X-Amz-Target: AnyScaleFrontendService.PutScalingPolicy
X-Amz-Date: 20160506T182145Z
User-Agent: aws-cli/1.10.23 Python/2.7.11 Darwin/15.4.0 botocore/1.4.8
Content-Type: application/x-amz-json-1.1
Authorization: AUTHPARAMS
{
    "PolicyName": "myscalablepolicy",
    "ServiceNamespace": "elasticache",
    "ResourceId": "replication-group/myscalablecluster",
    "ScalableDimension": "elasticache:replication-group:NodeGroups",
    "PolicyType": "TargetTrackingScaling",
    "TargetTrackingScalingPolicyConfiguration": {
        "TargetValue": 40.0,
        "PredefinedMetricSpecification":
        {
            "PredefinedMetricType": "ElastiCachePrimaryEngineCPUUtilization"
        }
    }
}
```