Auto Scaling can automatically adjust the number of ECS instances based on user-defined scaling rules...

 Auto Scaling is a service that automatically adjusts the number of ECS instances based on your business needs and policies. You can use Auto Scaling to cope with unpredictable or periodic workloads. Auto Scaling supports three scaling modes: scheduled, dynamic, and fixed1. Dynamic scaling mode allows you to automatically add or remove ECS instances based on CloudMonitor metrics, such as CPU utilization, memory utilization, inbound traffic, and outbound traffic2. You can configure scaling rules and scaling policies to define the conditions and actions for dynamic scaling. For example, you can set a scaling rule to add one ECS instance when the average CPU utilization of the scaling group exceeds 80% for five consecutive minutes3. Dynamic scaling mode is suitable for scenarios where you cannot predict service changes or do not have enough historical data to set a schedule4. References:

1: Auto Scaling overview - Auto Scaling - Alibaba Cloud Documentation Center1

2: Scaling modes - Auto Scaling - Alibaba Cloud Documentation Center2

3: Create a scaling rule - Auto Scaling - Alibaba Cloud Documentation Center3

4: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud5