Use PutScalingPolicy with a CLI

To add a target tracking scaling policy to an Auto Scaling group

The following put-scaling-policy example applies a target tracking scaling policy to the specified Auto Scaling group. The output contains the ARNs and names of the two CloudWatch alarms created on your behalf. If a scaling policy with the same name already exists, it will be overwritten by the new scaling policy.

aws autoscaling put-scaling-policy --auto-scaling-group-name my-asg \
  --policy-name alb1000-target-tracking-scaling-policy \
  --policy-type TargetTrackingScaling \
  --target-tracking-configuration file://config.json

Contents of config.json:

{
     "TargetValue": 1000.0,
     "PredefinedMetricSpecification": {
          "PredefinedMetricType": "ALBRequestCountPerTarget",
          "ResourceLabel": "app/my-alb/778d41231b141a0f/targetgroup/my-alb-target-group/943f017f100becff"
     }
}

Output:

{
     "PolicyARN": "arn:aws:autoscaling:region:account-id:scalingPolicy:228f02c2-c665-4bfd-aaac-8b04080bea3c:autoScalingGroupName/my-asg:policyName/alb1000-target-tracking-scaling-policy",
     "Alarms": [
         {
             "AlarmARN": "arn:aws:cloudwatch:region:account-id:alarm:TargetTracking-my-asg-AlarmHigh-fc0e4183-23ac-497e-9992-691c9980c38e",
             "AlarmName": "TargetTracking-my-asg-AlarmHigh-fc0e4183-23ac-497e-9992-691c9980c38e"
         },
         {
             "AlarmARN": "arn:aws:cloudwatch:region:account-id:alarm:TargetTracking-my-asg-AlarmLow-61a39305-ed0c-47af-bd9e-471a352ee1a2",
             "AlarmName": "TargetTracking-my-asg-AlarmLow-61a39305-ed0c-47af-bd9e-471a352ee1a2"
         }
     ]
 }

For more examples, see Example scaling policies for the AWS Command Line Interface (AWS CLI) in the Amazon EC2 Auto Scaling User Guide.

Example 1: This example adds the specified policy to the specified Auto Scaling group. The specified adjustment type determines how to interpret the ScalingAdjustment parameter. With 'ChangeInCapacity', a positive value increases the capacity by the specified number of instances and a negative value decreases the capacity by the specified number of instances.

Write-ASScalingPolicy -AutoScalingGroupName my-asg -AdjustmentType "ChangeInCapacity" -PolicyName "myScaleInPolicy" -ScalingAdjustment -1

Output:

arn:aws:autoscaling:us-west-2:123456789012:scalingPolicy:aa3836ab-5462-42c7-adab-e1d769fc24ef:autoScalingGroupName/my-asg
:policyName/myScaleInPolicy