A cooldown period refers to a period of lockdown time after a scaling activity in a scaling group is complete. During the cooldown period, the scaling group does not respond to scaling requests. You can configure a cooldown period to control the scaling frequency. This topic describes the rules and scenarios of the cooldown period feature. This topic also describes how to configure a cooldown period.
Overview of the cooldown period feature
A cooldown period is the minimum interval between two consecutive scaling activities that are triggered by event-triggered tasks. During the cooldown period, new scaling activities that are triggered by event-triggered tasks are rejected.
If you configure a cooldown period, Auto Scaling rejects only the scaling activities that are triggered by event-triggered tasks. Scaling activities that are triggered by other scaling tasks, such as manual execution of scheduled tasks and manual changing of the expected, minimum, or maximum number of instances, can be executed as expected.
Classification
Default Cooldown Time (Seconds): specifies the default cooldown period of scaling groups.
Cooldown Time: specifies the cooldown period of simple scaling rules that are defined in event-triggered tasks. If you do not configure this parameter, the value of the Default Cooldown Time (Seconds) parameter is automatically used.
Applicable scope
The cooldown period feature is applicable to scaling activities that are triggered by event-triggered tasks of the system monitoring type.
Calculation rules
After a scaling activity is triggered, the cooldown period begins when the last instance is added to or removed from the scaling group. If no instance is added to or removed from the scaling group after a scaling activity is triggered, the cooldown period does not start.
You can configure the Default Cooldown Time (Seconds) and Cooldown Time parameters at the same time. In this case, the value of the Cooldown Time parameter takes precedence.
ImportantThe first scaling activity that is triggered in a scaling group is not affected by the configured cooldown period.
Configure a cooldown period
Configure the Default Cooldown Time (Seconds) parameter of a scaling group
Modify the Default Cooldown Time (Seconds) parameter of an existing scaling group
Log on to the Auto Scaling console.
In the left-side navigation pane, click Scaling Groups.
In the top navigation bar, select the region where Auto Scaling is activated.
On the Scaling Groups page, find the scaling group whose Default Cooldown Time (Seconds) parameter you want to modify and click Details in the Actions column to go to the scaling group details page. In the Instance Scaling Overview section, click the
icon to open the Edit Instance Scaling Overview dialog box. Modify the Default Cooldown Time (Seconds) parameter based on your business requirements.
Click OK.
Configure the Default Cooldown Time (Seconds) parameter when you create a scaling group
When you create a scaling group on the Create by Form tab, you can configure the Default Cooldown Time (Seconds) parameter based on your business requirements, as shown in the following figure.
For information about how to create a scaling group, see Create a scaling group of the ECS type or Create a scaling group of the Elastic Container Instance type.
Configure the Cooldown Time parameter of a simple scaling rule
Modify the Cooldown Time parameter of an existing simple scaling rule
Log on to the Auto Scaling console.
In the left-side navigation pane, click Scaling Groups.
In the top navigation bar, select the region where Auto Scaling is activated.
On the Scaling Groups page, find the scaling group whose simple scaling rule you want to manage and click Details in the Actions column to go to the scaling group details page.
Choose . Find the scaling rule that you want to manage and click Edit in the Actions column to open the Edit Scaling Rule dialog box.
Modify the Cooldown Time parameter based on your business requirements.
Click OK.
Configure the Cooldown Time parameter when you create a simple scaling rule
When you create a simple scaling rule, you can configure the Cooldown Time parameter based on your business requirements, as shown in the following figure.
For more information about how to create a scaling rule, see Manage scaling rules.
References
For information about how to modify the default cooldown period of a scaling group by calling an API operation, see ModifyScalingGroup.
For information about how to modify the cooldown period of a simple scaling rule by calling an API operation, see ModifyScalingRule.