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    Auto Scaling:Create a scaling configuration for an ECS scaling group

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    Auto Scaling:Create a scaling configuration for an ECS scaling group

    Last Updated:Jul 17, 2026

    Create a scaling configuration to define the template that Auto Scaling uses to automatically create ECS instances during scale-out events.

    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

    1. Log on to the Auto Scaling console.

    2. In the navigation pane on the left, click Scaling Groups.

    3. In the top navigation bar, select a region.

    4. 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.

    5. At the top of the page, click the Scaling Configurations tab.

    6. On the Scaling Configuration tab, click Create Scaling Configuration.

    7. Configure parameters such as the billing method, instance and image, and network and security group.

      For parameter details, see Parameters.

    8. Click Create. On the Preview Scaling Configuration page, confirm the settings and click Create Order to create the scaling configuration.

    9. (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 for 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.

    • 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.

    Instance Configuration Mode

    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.

    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 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 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.

    Security Group

    A virtual firewall that controls network access for ECS instances.

    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).

    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

    Tags are key-value pairs that help you group and manage ECS instances.

    Note

    Tag keys and values are case-sensitive. Tags apply to all instances and cloud disks created from this scaling configuration.

    Advanced settings

    Parameter

    Description

    References

    Resource Group

    Group cloud resources by purpose, ownership, or permissions for easier management.

    Resource groups

    Instance Name

    Set a naming pattern to generate sequential, unique 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

    Set a hostname pattern to generate sequential, unique 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 User Data

    Run custom scripts or pass data to an instance during startup, such as obtaining software packages, enabling services, or printing logs.

    Note

    Instance user data is available only for VPC-based scaling groups.

    Customize instance initialization configurations

    Load Balancer Weight

    The weight assigned to ECS instances from this configuration when added as SLB backend servers. 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 security and compliance requirements. Create a dedicated host first, then Auto Scaling creates ECS instances on it.