Create an ECS scaling configuration - Auto Scaling - Auto Scaling

Create a scaling configuration to define the ECS instance template for scale-out events in your scaling group. Auto Scaling uses this template to automatically create ECS instances.

Prerequisites

An ECS-type scaling group is created. To specify instance attributes instead of a specific instance type, the scaling group must be in a VPC. Configure a scaling group.
A security group is created. For VPC-based scaling groups, the security group must belong to the same VPC. Create a security group.

Procedure

Log on to the Auto Scaling console.
In the navigation pane on the left, click Scaling Groups.
In the top navigation bar, select a region.
On the Scaling Groups page, find the target scaling group and click View Details in the Actions column to open the scaling group details page.
At the top of the page, click the Scaling Configurations tab.
On the Scaling Configuration tab, click Create Scaling Configuration.
Configure parameters such as the billing method, instance and image, and network and security group.

For parameter details, see Parameters.
Click Create. On the Preview Scaling Configuration page, confirm the settings and click Create Order to create the scaling configuration.
(Optional) Enable the scaling configuration.

After you click Create Order, the The scaling configuration is created. dialog box appears. You can click Enable to apply the scaling configuration immediately.

Note
You can also enable the scaling configuration later from the scaling configuration list. Apply or enable a scaling configuration.

Parameters

Basic information

Parameter

Description

References

Scaling Configuration Name

The scaling configuration name. Requirements:

2 to 40 characters in length.
Must start with a letter, digit, or Chinese character.
Can contain letters, digits, Chinese characters, periods (.), underscores (_), and hyphens (-).

None

Billing Method

Available billing methods:

Pay-as-you-go: Create and release resources on demand. You pay only for the resources you use.
Spot Instance: Spot instances are discounted compared to pay-as-you-go instances, but may be reclaimed. Use spot instances in suitable scenarios to reduce costs.

Instance and image

Parameter	Description	References
Select Image	An image provides the OS, application environment, and software required to create an ECS instance. Available image types: Public Image: OS images provided by Alibaba Cloud or third-party partners. Includes only the base system — you must configure applications separately. User-Defined Image: Images created from your instances or snapshots, including the OS, applications, and configurations. Eliminates repetitive setup. If you manually modify the custom image in a scaling configuration, the system disk size does not automatically adjust to match the new image. Manually update an image in a scaling configuration. If you create an update task in the Auto Scaling console, the system automatically creates a custom image for the source ECS instance and updates the scaling configuration when the task runs. Automatically update an image in a scaling configuration. Shared Image: Custom images shared by other Alibaba Cloud accounts. Alibaba Cloud does not guarantee the integrity or security of shared images. Use at your own risk. Marketplace Images: Reviewed, pre-built images with operating systems, application environments, and software. Deploy ECS instances with a single click without additional configuration for scenarios such as website building, application development, and visual management.	Image overview Public images Overview of custom images Share a custom image Marketplace images
Instance Configuration Mode	Different instance types suit different scenarios. Supported instance configuration modes: (Recommended) Specify Instance Attributes: Specify computing requirements (vCPUs, memory, instance family level, and maximum price) instead of exact instance types. The system filters matching types automatically. View selected types in the Preview Instance Types section. This improves the success rate of scale-out activities. Specify Instance Type: Select multiple instance types. If one type is out of stock, Auto Scaling uses another selected type. This improves the success rate of scale-out activities. Note You can set weights for different instance types based on performance metrics such as vCPUs. Use performance metrics to measure the capacity of a scaling group. If you select burstable instance types, the performance mode defaults to standard. You can enable unlimited mode. Overview of burstable performance instances.	Instance families
Select Instance Type	This parameter is available only when you set Instance Configuration Mode to Specify Instance Type. Select the required ECS instance types by name or by vCPU count. Note You can select up to 20 instance types. The scaling configuration prioritizes types that appear earlier in the list. After you select instance types, you can enable the following features: Enable Unlimited Mode for Burstable Instances: Available only for burstable instance types. Allows applications to exceed baseline performance at any time. Performance modes. Use vCPUs to calculate the capacity of the scaling group: Set a weight for each selected instance type. When vCPUs measure scaling group capacity, the current capacity is recalculated, potentially triggering a new scaling activity. You can also use other metrics such as memory size. Use performance metrics to measure the capacity of a scaling group.	Instance families
Instance Attribute Combination	This parameter is available only when you set Instance Configuration Mode to Specify Instance Attributes. Select instance types based on attributes such as vCPUs, memory, instance family level, and maximum price. View selected types in the Preview Instance Types section. Note You can select Add More Attribute Filters to filter by architecture or burstable instance attributes, or select Specify Instance Types that Must Be Included to specify exact instance types.	Instance families

Storage

Parameter	Description	References
System Disk	Select a ESSD cloud disk, Standard SSD, Ultra Disk, or ESSD AutoPL system disk.	What is block storage? Disk overview
Configure More System Disk Categories	Specify multiple system disk categories, including Basic Disk, Standard SSD, Ultra Disk, ESSD cloud disk, and ESSD AutoPL. This reduces scale-out failures caused by disk category mismatches. Auto Scaling selects the first matching category in the specified order.
Data Disk	Set the number of data disks for your storage needs. To add a data disk, click Add Data Disk (0/16) or the icon and specify the disk size and quantity. If you want to create a data disk from a snapshot, you can also click Create from Snapshot and select a snapshot. To delete a data disk, click the icon in the data disk section.
Configure More Data Disk Categories	If you configure a Data Disk, you can specify multiple data disk categories, such as Basic Disk, Standard SSD, Ultra Disk, ESSD cloud disk, and ESSD AutoPL. This reduces scale-out failures caused by disk category mismatches.

Network and security group

Parameter	Description	References
Public IP Address	Assign a public IPv4 address to an ECS instance. If you assign a public IP address, specify a Bandwidth Billing Mode: By Traffic or Pay-by-bandwidth. By Traffic: Charged based on actual outbound traffic. Suitable for variable bandwidth needs with occasional spikes. Set a Maximum Bandwidth to cap maximum bandwidth. Important Pay-as-you-go billing. Charged per GB of traffic on an hourly basis. Ensure your account has sufficient balance. Pay-by-bandwidth: Specify a fixed outbound bandwidth (the Bandwidth value), such as 10 Mbit/s. Suitable for stable bandwidth needs and costs less than By Traffic.	IP addresses in a VPC IP addresses in the classic network Public bandwidth billing
Security Group	A virtual firewall that controls network access for ECS instances.	Overview of security groups Create a security group

Management settings

Parameter	Description	References
Logon Credentials	Supported logon methods vary by OS: Linux: Key Pair, Custom Password, or Set Later (set the password after instance creation). Windows: Custom Password or Set Later (set the password after instance creation).	Overview of SSH key pairs Reset the logon password of an instance
Key Pair	This parameter is available only when you set Logon Credentials to Key Pair. A key pair consists of a public key and a private key file. Only I/O optimized instances support key pairs. When key pair logon is selected, username and password-based logon is disabled by default.	Create an SSH key pair
Tag	A key-value pair that identifies a resource. Tags help you group and manage related ECS instances. Note Tag keys and values are case-sensitive. Tags apply to all instances and cloud disks created from this scaling configuration.	Tags Create and bind tags

Advanced settings

Parameter	Description	References
Resource Group	Group cloud resources by purpose, ownership, or permissions for easier management.	Resource groups
Instance Name	An ordered and unique naming pattern generates sequential names for ECS instances created during scale-out events. If not specified, the system uses a default name.	Set ordered and unique rules for instance names or hostnames
Host	An ordered and unique hostname pattern generates sequential hostnames for ECS instances created during scale-out events. If not specified, the system uses a default hostname.
RAM Role	An instance RAM role lets you make API calls from an ECS instance using temporary credentials instead of your permanent AccessKey. Note Instance RAM roles are available only for VPC-based scaling groups.	Instance RAM roles
Instance User Data	Run custom scripts or pass data to an instance during startup, such as obtaining software packages, enabling services, or printing logs. Prepare a custom script and pass it to the ECS instance through this feature. Note Instance user data is available only for VPC-based scaling groups.	Customize instance initialization configurations
Load Balancer Weight	The weight of an ECS instance from this configuration when added as a backend server to an SLB instance. Valid values: 1 to 100. A weight specified when attaching an SLB instance to the scaling group takes precedence.	Add and remove SLB instances for a scaling group
Resource Pool Policy	Resource pools include private pools (from Elastic Assurance or Capacity Reservation) and public pools. Not Use: Does not use a resource pool policy. Private Pool Prioritized: Prioritizes the specified private pool. Falls back to open-type private pools, then the public pool if capacity is insufficient. Private Pool Only: Requires a specified private pool. The instance fails to start if the pool has insufficient capacity.	Overview of Resource Butler
Dedicated Host	A dedicated host provides exclusive physical resources, avoiding resource contention with other tenants and meeting strict security and compliance requirements. Create a dedicated host in the console, then Auto Scaling creates ECS instances on the specified dedicated host.	What is a dedicated host (DDH)? Create a DDH