Amazon EC2 Auto Scaling
User Guide

Add a Scaling Policy to an Existing Auto Scaling Group

Use the console to add a scaling policy to an existing Auto Scaling group.

To update an Auto Scaling group with scaling based on metrics

  1. Open the Amazon EC2 console at

  2. On the navigation pane, under Auto Scaling, choose Auto Scaling Groups.

  3. Select the Auto Scaling group.

  4. On the Scaling Policies tab, choose Add policy.

  5. If you are adding a target tracking scaling policy, use the following steps. If you are using a simple or step scaling policy, skip to the next step.

    1. For Name, type a name for the policy.

    2. Choose a Metric type and specify a Target value for the metric.

    3. Specify an instance warm-up value for Instances need, which allows you to control the amount of time until a newly launched instance can contribute to the CloudWatch metrics.

    4. Check the Disable scale-in option if you only want a scale-out policy created. This allows you to create a separate scale-in policy if wanted.

    5. Choose Create.

  6. If you are using a step scaling policy, do the following:

    1. For Name, type a name for the policy, and then choose Create new alarm.

    2. On the Create Alarm page, choose create topic. For Send a notification to, type a name for the SNS topic. For With these recipients, type one or more email addresses to receive notification. If you want, you can replace the default name for your alarm with a custom name. Next, specify the metric and the criteria for the alarm, using Whenever, Is, and For at least. Choose Create Alarm.

    3. Specify the scaling activity for the policy using Take the action. By default, the lower bound for this step adjustment is the alarm threshold and the upper bound is null (positive infinity). To add another step adjustment, choose Add step.

      (Optional) We recommend that you use the default to create both scaling policies with steps. To create simple scaling policies, choose Create a simple scaling policy. For more information, see Scaling Policy Types.

    4. Choose Create.