Creates a scaling rule.
Operation description
Description
A scaling rule defines a specific scaling activity, such as adding or removing N instances. If the number of Elastic Compute Service (ECS) instances in a scaling group is less than the minimum number allowed or greater than the maximum number allowed after a scaling rule is executed, Auto Scaling adjusts the number of ECS instances that you want to add or remove. This way, the number of ECS instances can be maintained within the valid range after the scaling rule is executed. The number of ECS instances that is specified in the scaling rule remains unchanged. Example:
- If your scaling group contains two ECS instances and allows up to three ECS instances, only one ECS instance is added to your scaling group after you execute a scale-out rule in which three ECS instances are specified. The number of ECS instances that is specified in the scaling rule remains unchanged.
- If your scaling group contains three ECS instances and requires at least two ECS instances, only one ECS instance is removed from your scaling group after you execute a scale-in rule in which five ECS instances are specified. The number of ECS instances that is specified in the scaling rule remains unchanged.
Before you call this operation, take note of the following items:
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If you set the AdjustmentType parameter to TotalCapacity, the number of ECS instances in the scaling group is adjusted to the specified value. The value of the AdjustmentValue parameter must be greater than or equal to 0.
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If you set the AdjustmentType parameter to QuantityChangeInCapacity or PercentChangeInCapacity, a positive value of AdjustmentValue specifies the number of ECS instances that are added to the scaling group, and a negative value of AdjustmentValue specifies the number of ECS instances that are removed from the scaling group.
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If you set the AdjustmentType parameter to PercentChangeInCapacity, Auto Scaling uses the following formula to calculate a value, and then rounds the value to the nearest integer to obtain the number of ECS instances that need to be scaled: Value of TotalCapacity × Value of AdjustmentValue/100.
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If the cooldown time is specified in a scaling rule, the specified time applies to the scaling group after the rule is executed. Otherwise, the value of the DefaultCooldown parameter of the scaling group applies to the scaling group.
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You can create only a limited number of scaling rules for a scaling group. For more information, see the "Limits" topic.
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The unique identifier (ScalingRuleAri) of a scaling rule can be used by the following operations:
- ExecuteScalingRule: You can call this operation to manually execute a specific scaling rule by setting the ScalingRuleAri parameter to the unique identifier of the scaling rule.
- CreateScheduledTask: You can call this operation to create a scheduled task for a specific scaling rule by setting the ScheduledAction parameter to the unique identifier of the scaling rule.
Debugging
Authorization information
The following table shows the authorization information corresponding to the API. The authorization information can be used in the Action policy element to grant a RAM user or RAM role the permissions to call this API operation. Description:
- Operation: the value that you can use in the Action element to specify the operation on a resource.
- Access level: the access level of each operation. The levels are read, write, and list.
- Resource type: the type of the resource on which you can authorize the RAM user or the RAM role to perform the operation. Take note of the following items:
- The required resource types are displayed in bold characters.
- If the permissions cannot be granted at the resource level,
All Resourcesis used in the Resource type column of the operation.
- Condition Key: the condition key that is defined by the cloud service.
- Associated operation: other operations that the RAM user or the RAM role must have permissions to perform to complete the operation. To complete the operation, the RAM user or the RAM role must have the permissions to perform the associated operations.
| Operation | Access level | Resource type | Condition key | Associated operation |
|---|---|---|---|---|
| ess:CreateScalingRule | Write |
|
| none |
Request parameters
| Parameter | Type | Required | Description | Example |
|---|---|---|---|---|
| ScalingGroupId | string | Yes | The ID of the scaling group to which the scaling rule belongs. | asg-bp1ffogfdauy0jw0**** |
| ScalingRuleName | string | No | The name of the scaling rule. It must be 2 to 64 characters in length, and can contain letters, digits, underscores (_), hyphens (-), and periods (.). It must start with a letter or a digit. The name of a scaling rule must be unique in the scaling group to which the scaling rule belongs and within an Alibaba Cloud account. If you do not specify this parameter, the value of the ScalingRuleId parameter is used. | scalingrule**** |
| Cooldown | integer | No | The cooldown time of the scaling rule. This parameter is available only if you set the ScalingRuleType parameter to SimpleScalingRule. Valid values: 0 to 86400. Unit: seconds. By default, this parameter is left empty. | 60 |
| MinAdjustmentMagnitude | integer | No | The minimum number of instances that must be scaled when the AdjustmentType parameter is set to PercentChangeInCapacity. This parameter takes effect only if you set the ScalingRuleType parameter to SimpleScalingRule or StepScalingRule. | 1 |
| AdjustmentType | string | No | The scaling method of the scaling rule. This parameter is required only if you set the ScalingRuleType parameter to SimpleScalingRule or StepScalingRule. Valid values:
| QuantityChangeInCapacity |
| AdjustmentValue | integer | No | The number of instances that must be scaled based on the scaling rule. This parameter is required only if you set the ScalingRuleType parameter to SimpleScalingRule or StepScalingRule. The number of ECS instances that are scaled in a single scaling activity cannot exceed 1,000.
| 100 |
| ScalingRuleType | string | No | The type of the scaling rule. Valid values:
Default value: SimpleScalingRule. | SimpleScalingRule |
| EstimatedInstanceWarmup | integer | No | The warmup period of an instance. This parameter is available only if you set the ScalingRuleType parameter to TargetTrackingScalingRule or PredictiveScalingRule. Auto Scaling adds ECS instances that are in the warmup state to a scaling group but does not report monitoring data to CloudMonitor during the warmup period. Note
Auto Scaling calculates the number of ECS instances that must be scaled. ECS instances in the warmup state are not counted towards the current capacity of the scaling group.
Valid values: 0 to 86400. Unit: seconds. Default value: 300. | 300 |
| MetricName | string | No | The predefined metric that you want to monitor. This parameter is required only if you set the ScalingRuleType parameter to TargetTrackingScalingRule or PredictiveScalingRule. Valid values if you set the ScalingRuleType parameter to TargetTrackingScalingRule:
Valid values if you set the ScalingRuleType parameter to PredictiveScalingRule:
| CpuUtilization |
| TargetValue | float | No | The target value. This parameter is required only if you set the ScalingRuleType parameter to TargetTrackingScalingRule or PredictiveScalingRule. The value must be greater than 0 and can have up to three decimal places. | 0.125 |
| DisableScaleIn | boolean | No | Specifies whether to disable scale-in. This parameter is available only if you set the ScalingRuleType parameter to TargetTrackingScalingRule. Default value: false. | false |
| ScaleInEvaluationCount | integer | No | The number of consecutive times that the event-triggered task created for scale-in activities must meet the threshold conditions before an alert is triggered. After a target tracking scaling rule is created, an event-triggered task is automatically created and then associated with the target tracking scaling rule. Default value: 15. | 15 |
| ScaleOutEvaluationCount | integer | No | The number of consecutive times that the event-triggered task created for scale-out activities must meet the threshold conditions before an alert is triggered. After a target tracking scaling rule is created, an event-triggered task is automatically created and then associated with the target tracking scaling rule. Default value: 3. | 3 |
| PredictiveScalingMode | string | No | The mode of the predictive scaling rule. Valid values:
Default value: PredictAndScale. | PredictAndScale |
| PredictiveValueBehavior | string | No | The maximum value for predication tasks. Valid values:
Default value: MaxOverridePredictiveValue. | MaxOverridePredictiveValue |
| PredictiveValueBuffer | integer | No | The percentage of the increment to the predicted value when the PredictiveValueBehavior parameter is set to PredictiveValueOverrideMaxWithBuffer. If the predicted value increased by this percentage is greater than the initial maximum capacity, the increased value is used as the maximum value for prediction tasks. Valid values: 0 to 100. Default value: 0. | 50 |
| PredictiveTaskBufferTime | integer | No | The amount of buffer time before the prediction task is executed. By default, all prediction tasks that are automatically created for a predictive scaling rule are executed on the hour. You can specify an amount of buffer time for resource preparation before the prediction tasks are executed. Valid values: 0 to 60. Unit: minutes. Default value: 0. | 30 |
| InitialMaxSize | integer | No | The maximum number of ECS instances in the scaling group. If you specify this parameter, you must also specify the PredictiveValueBehavior parameter. The default value of this parameter is the value of the MaxSize parameter. | 100 |
| StepAdjustments | object [] | No | Details of the step adjustments. | |
| MetricIntervalUpperBound | float | No | The upper limit that is specified in a step adjustment. Valid values: -9.999999E18 to 9.999999E18. | 5.0 |
| ScalingAdjustment | integer | No | The number of ECS instances that you want to scale in a step adjustment. This parameter is available only if you set the ScalingRuleType parameter to StepScalingRule. | 1 |
| MetricIntervalLowerBound | float | No | The lower limit specified in a step adjustment. This parameter is available only if you set the ScalingRuleType parameter to StepScalingRule. Valid values: -9.999999E18 to 9.999999E18. | 1.0 |
| RegionId | string | No | The region ID of the scaling group. | cn-hangzhou |
Response parameters
Examples
Sample success responses
JSONformat
{
"ScalingRuleAri": "ari:acs:ess:cn-hangzhou:140692647406****:scalingrule/asr-bp1dvirgwkoowxk7****",
"RequestId": "473469C7-AA6F-4DC5-B3DB-A3DC0DE3****",
"ScalingRuleId": "asr-bp1dvirgwkoowxk7****"
}Error codes
For a list of error codes, visit the Service error codes.
Change history
| Change time | Summary of changes | Operation | ||||
|---|---|---|---|---|---|---|
| 2023-04-03 | The request parameters of the API has changed | see changesets | ||||
|