Create a scaling group from an existing instance

Common scenarios

A scaling group is a collection of ECS instances that share the same application scenario and instance type. Scaling groups automatically adjust instance count based on load. Examples:

Procedure

The following steps create a scaling group from an existing instance. You can also create a scaling group with other methods.

1. Open the Create Scaling Group page.

   1. Sign in to the Auto Scaling console.

   2. In the left-side navigation pane, click Scaling Groups.

   3. In the top navigation bar, select the region where Auto Scaling is activated.

   4. On the Scaling Groups page, click Create to go to the Create Scaling Group page.

2. Click the Create by Form tab and configure the scaling group as prompted.

   The following table describes the required parameters. See Create an ECS scaling group for all parameters.

   Required parameters

   Parameter	Description
   Scaling Group Name	The scaling group name. Must meet the requirements displayed on the console.
   Type	The instance type. Select ECS.
   Instance Configuration Source	Select Select Existing Instance. The scaling group uses this instance's configuration to create a default scaling configuration for new instances.
   Select Existing Instance	Select an existing ECS instance. Auto Scaling extracts its basic configurations to create a default scaling configuration. Important Extracted configurations include Instance Type, Network Type, Security Group ID, Image ID, and other basic configurations, but exclude logon password and tags.
   Minimum Number of Instances	The minimum number of instances. When the actual count drops below this limit, Auto Scaling triggers a scale-out event.
   Maximum Number of Instances	The maximum number of instances. When the actual count exceeds this limit, Auto Scaling automatically removes instances.
   Default Cooldown Time (Seconds)	The cooldown time after a scaling activity, in seconds. Default value: 300.
   VPC	The VPC for all instances in the scaling group. Important The VPC cannot be changed after the scaling group is created.
   vSwitch	Select vSwitches in your VPC for instance communication. Important Select vSwitches in multiple zones to avoid instance creation failures due to insufficient inventory. Use Scaling Policy to control instance distribution across zones.

3. Click Create.

Next steps

• Update the scaling configuration image: The scaling configuration uses the base image of the selected instance by default. To replicate the instance's configurations and environment, create a custom image from the instance and update the scaling configuration image.

• Configure automatic scaling policies: Set up scaling solutions based on your business requirements.

• Add existing instances: Manually add the original instance to the scaling group for unified management.