	Function	Function description
AS Parameters	Number of AS instances	Expected number of instances, minimum and maximum number of instances in the AS group, and the number or percentage of ECS instances increased or decreased based on the AS policy
	Multiple capacity expansion and reduction policies	It supports multiple capacity expansion and reduction policies. Priority policy and balanced distribution policy
	Multi-AZ AS	You can assign multiple AZs when setting an AS group. Storage capacity can be expanded or decreased among multiple AZs in the same resource pool for ECS instances.
	Cooldown time	Users can customize a cooldown period for scaling activities. Scaling activities triggered by alarm policies are denied by the AS group during the cooldown period, and scaling activities triggered by other types of AS policies such as scheduled and periodic policies are not restricted. The system resets the cooldown time each time a scaling activity is triggered.
	Load balance	After load balancer is used, ELB automatically distributes the access traffic to all ECS instances in the AS group to extend the service capabilities of the application system and guarantee higher levels of application fault tolerance.
	Health check	Health check is supported to ensure that services are carried by a healthy ECS. It supports ECS and LB health checks to automatically replace unhealthy instances.
AS configuration	Custom AS instance specification	Users can define the specifications of the ECS to be added in the AS group, including ECS CPU, memory, image and login mode. When it is necessary to add an ECS triggered by the AS policy, a new ECS will be created according to the predefined ECS specifications and be added to the AS group.
AS policy	Multiple AS policies	It supports multiple dynamic AS policies, and could dynamically increase or decrease the number of ECS according to indicators such as CPU and memory utilization of ECSs based on the alarm rules set by users. It could also increase or decrease the number of ECS instances regularly or periodically.
AS log	AS data observability	Users can view the change in the number of ECS instances in the AS group in graphs or tables, as well as the resource utilization of all ECS instances in the AS group and the change curve of the average value.

Auto Scaling

Features