This topic describes the feature and quantity limits of Auto Scaling.

Feature limits

Auto Scaling has the following feature limits:
  • Auto Scaling can automatically scale the number of ECS instances in a scaling group, but cannot automatically upgrade or downgrade configurations of ECS instances, such as vCPUs, memory, and bandwidth.
  • Applications deployed on ECS instances in a scaling group must be stateless and horizontally scalable.
  • ECS instances in a scaling group can be automatically released. We recommend that you do not store information such as sessions, application data, or logs on ECS instances in a scaling group. If applications deployed on these ECS instances require data to be stored, store status information such as sessions on ECS instances that are not in a scaling group, store application data in ApsaraDB for RDS, and store logs in Log Service. For more information, see What is ApsaraDB for RDS? and What is Log Service?
  • Auto Scaling cannot automatically add ECS instances to the whitelist of an ApsaraDB for Memcache instance. You must manually add these ECS instances to the whitelist. For more information, see Set IP firewall.

Quantity limits

The following table describes the quantity limits that apply to Auto Scaling in a single account.
Item Limit
Total number of scaling groups in a region The quota is based on the resource usage of Auto Scaling. Go to the Quotas page to view the quota.
Note You can submit a ticket to apply for increasing the quota.
Total number of scaling configurations in a scaling group
Total number of scaling rules in a scaling group
Total number of ApsaraDB for RDS instances that can be associated with a scaling group
Total number of SLB instances that can be associated with a scaling group
Total number of VServer groups that can be associated with a scaling group
Maximum number of ECS instances that can be configured for a scaling group
Total number of scheduled tasks in a region
Total number of ECS instances that can be added to or deleted from a scaling group during a scaling activity 500
Total number of instance types in a scaling configuration 10
Total number of event notifications in a scaling group 6
Total number of lifecycle hooks in a scaling group 6