You can specify an instance type for your scaling configuration. If the specified instance type does not have sufficient inventory or is retired, the scale-out activities may fail. We recommend that you use the intelligent configuration feature. This way, you need to configure only information such as vCPUs and memory size based on your business requirements. Auto Scaling selects an instance type based on your configurations to effectively execute scale-out activities.

Background information

The intelligent configuration feature automatically selects an instance type based on your business requirements. You need to specify the number of vCPUs, memory size, instance family, and maximum price. Then, the system selects an instance type based on your configurations to create Elastic Compute Service (ECS) instances. The intelligent configuration feature can help you resolve the following issues:

  • If you have one or more instance types in your scaling configuration, but the specified instance types do not have sufficient inventory or are retired, the scale-out activities may fail. In this case, you must manually modify your scaling configuration.
  • If you are unable to determine which instance type is suitable for your business scenario, you can use the intelligent configuration feature.

Limits

  • The intelligent configuration feature can be used only if your scaling configuration resides in a virtual private cloud (VPC).
  • The intelligent configuration feature allows you to specify up to 10 configuration scopes.
    Note A configuration scope consists of the number of vCPUs, memory size, instance family level, and maximum price.
  • If you want to configure the Instance Type parameter and use the intelligent configuration feature at the same time, take note of the following limits:
    • You cannot set weights for instance types.
    • If you set the billing method in the scaling configuration to Preemptible Instance and set the bidding method to Set Maximum Price, you must specify the bid price in the intelligent configuration mode.

Procedure

The following section provides an example on how to use the intelligent configuration feature and how the configuration takes effect.

  1. Create a VPC-type scaling group. For more information, see Create a scaling group.
    In this example, Minimum Number of Instances is set to 0 and Maximum Number of Instances is set to 2.
  2. Configure the parameters shown in the following figure to create and enable a scaling configuration. Make sure that Intelligent Configuration is selected. For more information, see Create a scaling configuration.
    Scaling configuration

    In this example, Billing Method is set to Pay-As-You-Go. Both Instance Type and Intelligent Configuration are selected for Instance Configuration Mode.

    • Instance Type: In this example, ecs.g5.large is selected. You cannot set a weight for the instance because Intelligent Configuration is selected. During scale-out, Auto Scaling automatically selects the specified instance type to create ECS instances.
    • The following table describes the parameters that you need to configure when you use the intelligent configuration feature.
      Parameter Description Example
      vCPUs The number of vCPUs of the ECS instance. 2 vCPUs
      Memory The memory size of the ECS instance. 8 GiB
      Instance Family Level
      • Entry Level: Instances of this level have lower costs, but the computing performance of the instances cannot be ensured. This level is suitable for business scenarios in which CPU utilization is low. For more information, see Shared instance families.
      • Enterprise Level: Instances of this level provide stable computing performance and dedicated resources. This level is suitable for business scenarios that require high service stability. For more information, see Instance families.
      • Credit Entry Level: Instances of this level use CPU credits to ensure computing performance. This level is suitable for business scenarios in which CPU utilization is usually low but bursts of CPU utilization may occur. For more information, see Overview.
      Enterprise Level
      Maximum Price The maximum price per hour for the pay-as-you-go instance. This parameter is optional.

      If you set Billing Method to Preemptible Instance, take note of the following items:

      • If the market price of an instance is higher than the specified maximum price, the instance is released.
      • If you select both Instance Type and Intelligent Configuration for Instance Configuration Mode and set the bidding method to Set Maximum Price, you must configure this parameter.
      None
      You can click View Matching Result to view the available instance types for scale-out activities, as shown in the following figure. If the specified instance type does not have sufficient inventory or is retired, Auto Scaling selects the instance type that is available at the lowest price from the matching result to create ECS instances. View Matching Result
  3. Enable the scaling group. For more information, see Enable a scaling group.
    Auto Scaling does not automatically trigger a scaling activity if Minimum Number of Instances is set to 0. In this case, the total number of instances in the scaling group is 0.
  4. Create a scaling rule. For more information, see Create a scaling rule.
    In this example, the scaling rule that adds one ECS instance is created.
  5. Execute the scaling rule. For more information, see Execute a scaling rule.
    After the scaling rule is executed, you can view the ECS instance that is added. If the instance type ecs.g5.large does not have sufficient inventory, Auto Scaling automatically selects instance types that are matched by using Intelligent Configuration and available at the lowest price to create ECS instances. In this example, an ECS instance of the ecs.g5ne.large instance type is created. The intelligent configuration feature helps you prevent scale-out failures that are caused by the insufficient inventory of the specified instance type. This increases the probability of success for scale-out activities.