PutScalingPolicy

Creates or updates a scaling policy for an Application Auto Scaling scalable target.

Each scalable target is identified by a service namespace, resource ID, and scalable dimension. A scaling policy applies to the scalable target identified by those three attributes. You cannot create a scaling policy until you have registered the resource as a scalable target.

Multiple scaling policies can be in force at the same time for the same scalable target. You can have one or more target tracking scaling policies, one or more step scaling policies, or both. However, there is a chance that multiple policies could conflict, instructing the scalable target to scale out or in at the same time. Application Auto Scaling gives precedence to the policy that provides the largest capacity for both scale out and scale in. For example, if one policy increases capacity by 3, another policy increases capacity by 200 percent, and the current capacity is 10, Application Auto Scaling uses the policy with the highest calculated capacity (200% of 10 = 20) and scales out to 30.

We recommend caution, however, when using target tracking scaling policies with step scaling policies because conflicts between these policies can cause undesirable behavior. For example, if the step scaling policy initiates a scale-in activity before the target tracking policy is ready to scale in, the scale-in activity will not be blocked. After the scale-in activity completes, the target tracking policy could instruct the scalable target to scale out again.

For more information, see Target tracking scaling policies and Step scaling policies in the Application Auto Scaling User Guide.

Request Syntax

{
   "PolicyName": "string",
   "PolicyType": "string",
   "ResourceId": "string",
   "ScalableDimension": "string",
   "ServiceNamespace": "string",
   "StepScalingPolicyConfiguration": { 
      "AdjustmentType": "string",
      "Cooldown": number,
      "MetricAggregationType": "string",
      "MinAdjustmentMagnitude": number,
      "StepAdjustments": [ 
         { 
            "MetricIntervalLowerBound": number,
            "MetricIntervalUpperBound": number,
            "ScalingAdjustment": number
         }
      ]
   },
   "TargetTrackingScalingPolicyConfiguration": { 
      "CustomizedMetricSpecification": { 
         "Dimensions": [ 
            { 
               "Name": "string",
               "Value": "string"
            }
         ],
         "MetricName": "string",
         "Metrics": [ 
            { 
               "Expression": "string",
               "Id": "string",
               "Label": "string",
               "MetricStat": { 
                  "Metric": { 
                     "Dimensions": [ 
                        { 
                           "Name": "string",
                           "Value": "string"
                        }
                     ],
                     "MetricName": "string",
                     "Namespace": "string"
                  },
                  "Stat": "string",
                  "Unit": "string"
               },
               "ReturnData": boolean
            }
         ],
         "Namespace": "string",
         "Statistic": "string",
         "Unit": "string"
      },
      "DisableScaleIn": boolean,
      "PredefinedMetricSpecification": { 
         "PredefinedMetricType": "string",
         "ResourceLabel": "string"
      },
      "ScaleInCooldown": number,
      "ScaleOutCooldown": number,
      "TargetValue": number
   }
}

Request Parameters

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

The request accepts the following data in JSON format.

Response Syntax

{
   "Alarms": [ 
      { 
         "AlarmARN": "string",
         "AlarmName": "string"
      }
   ],
   "PolicyARN": "string"
}

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

Errors

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

Examples

If you plan to create requests manually, you must replace the Authorization header contents in the examples (AUTHPARAMS) with a signature. For more information, see Signing AWS API requests in the IAM User Guide. If you plan to use the AWS CLI or one of the AWS SDKs, these tools sign the requests for you.

Example of a target tracking scaling policy

The following example applies a target tracking scaling policy to an Amazon ECS service called web-app in the default cluster. The policy keeps the average CPU utilization of the service at 75 percent, with scale-out and scale-in cooldown periods of 60 seconds. The output contains the ARNs and names of the two CloudWatch alarms created on your behalf.

Sample Request

POST / HTTP/1.1
Host: application-autoscaling.us-west-2.amazonaws.com
Accept-Encoding: identity
Content-Length: [content-length]
X-Amz-Target: AnyScaleFrontendService.PutScalingPolicy
X-Amz-Date: 20190506T191044Z
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": "cpu75-target-tracking-scaling-policy",
    "PolicyType": "TargetTrackingScaling",
    "TargetTrackingScalingPolicyConfiguration": {
        "TargetValue": 75.0,
        "PredefinedMetricSpecification": {
            "PredefinedMetricType": "ECSServiceAverageCPUUtilization"
        },
        "ScaleOutCooldown": 60,
        "ScaleInCooldown": 60
    },
    "ServiceNamespace": "ecs",
    "ScalableDimension": "ecs:service:DesiredCount",
    "ResourceId": "service/my-cluster/my-service"
}

Sample Response

HTTP/1.1 200 OK
x-amzn-RequestId: [request-id]
Content-Type: application/x-amz-json-1.1
Content-Length: 314
Date: Fri, 06 May 2019 19:10:44 GMT

{
    "PolicyARN": "arn:aws:autoscaling:us-west-2:012345678910:scalingPolicy:6d8972f3-efc8-437c-92d1-6270f29a66e7:resource/ecs/service/my-cluster/my-service:policyName/cpu75-target-tracking-scaling-policy",
    "Alarms": [
        {
            "AlarmARN": "arn:aws:cloudwatch:us-west-2:012345678910:alarm:TargetTracking-service/my-cluster/my-service-AlarmHigh-d4f0770c-b46e-434a-a60f-3b36d653feca",
            "AlarmName": "TargetTracking-service/my-cluster/my-service-AlarmHigh-d4f0770c-b46e-434a-a60f-3b36d653feca"
        },
        {
            "AlarmARN": "arn:aws:cloudwatch:us-west-2:012345678910:alarm:TargetTracking-service/my-cluster/my-service-AlarmLow-1b437334-d19b-4a63-a812-6c67aaf2910d",
            "AlarmName": "TargetTracking-service/my-cluster/my-service-AlarmLow-1b437334-d19b-4a63-a812-6c67aaf2910d"
        }
    ]
}

Example of a step scaling policy for scale out

The following example applies a step scaling policy to an Amazon ECS service called web-app in the default cluster. The policy increases the desired count of the service by 200%, with a cooldown period of 60 seconds. The output includes the ARN for the policy, which you use to create the CloudWatch alarm.

Sample Request

POST / HTTP/1.1
Host: application-autoscaling.us-west-2.amazonaws.com
Accept-Encoding: identity
Content-Length: [content-length]
X-Amz-Target: AnyScaleFrontendService.PutScalingPolicy
X-Amz-Date: 20190506T191138Z
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": "my-scale-out-policy",
    "PolicyType": "StepScaling",
    "StepScalingPolicyConfiguration": {
        "AdjustmentType": "PercentChangeInCapacity",
        "Cooldown": 60,
        "MetricAggregationType": "Average",
        "StepAdjustments": [
            {
                "ScalingAdjustment": 200,
                "MetricIntervalLowerBound": 0
            }
        ]
    },
    "ServiceNamespace": "ecs",
    "ScalableDimension": "ecs:service:DesiredCount",
    "ResourceId": "service/my-cluster/my-service"
}

Sample Response

HTTP/1.1 200 OK
x-amzn-RequestId: [request-id]
Content-Type: application/x-amz-json-1.1
Content-Length: 175
Date: Fri, 06 May 2019 19:11:38 GMT

{
    "PolicyARN": "arn:aws:autoscaling:us-west-2:012345678910:scalingPolicy:ac542982-cbeb-4294-891c-a5a941dfa787:resource/ecs/service/my-cluster/my-service:policyName/my-scale-out-policy"
}

Example of a step scaling policy for scale in

The following example applies a step scaling policy to the same Amazon ECS service as in the preceding example. The policy has two step adjustments that decrease the desired count of the service by 25% or 50%, depending on the size of the alarm breach, with a cooldown period of 120 seconds. The output includes the ARN for the policy, which you use to create the CloudWatch alarm.

Sample Request

POST / HTTP/1.1
Host: application-autoscaling.us-west-2.amazonaws.com
Accept-Encoding: identity
Content-Length: [content-length]
X-Amz-Target: AnyScaleFrontendService.PutScalingPolicy
X-Amz-Date: 20190506T191152Z
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": "my-scale-in-policy",
    "PolicyType": "StepScaling",
    "StepScalingPolicyConfiguration": {
        "AdjustmentType": "PercentChangeInCapacity",
        "Cooldown": 120,
        "MetricAggregationType": "Average",
        "MinAdjustmentMagnitude": 1,
        "StepAdjustments": [
            {
                "ScalingAdjustment": -25,
                "MetricIntervalLowerBound": -15,
                "MetricIntervalUpperBound": 0
             },
            {
                "ScalingAdjustment": -50,
                "MetricIntervalUpperBound": -15
            }
        ]
    },
    "ServiceNamespace": "ecs",
    "ScalableDimension": "ecs:service:DesiredCount",
    "ResourceId": "service/my-cluster/my-service"
}

Sample Response

HTTP/1.1 200 OK
x-amzn-RequestId: [request-id]
Content-Type: application/x-amz-json-1.1
Content-Length: 174
Date: Fri, 06 May 2019 19:11:52 GMT
            
{
    "PolicyARN": "arn:aws:autoscaling:us-west-2:012345678910:scalingPolicy:6d8972f3-efc8-437c-92d1-6270f29a66e7:resource/ecs/service/my-cluster/my-service:policyName/my-scale-in-policy"
}

See Also

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