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. Therefore, 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 independent ECS instances, 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 of Auto Scaling.
Item Initial quota How to increase the quota
Scaling groups within the same region and in the same account 100 Auto Scaling automatically increases the quota based on your usage. A maximum of 440 scaling groups can be created per region in an account.
Scaling configurations in a scaling group 20 Auto Scaling automatically increases the quota based on your usage. A maximum of 140 scaling configurations can be created for a scaling group.
Scaling rules in a scaling group 20 Auto Scaling automatically increases the quota based on your usage. A maximum of 140 scaling rules can be created for a scaling group.
Event notifications in a scaling group 6 N/A
Lifecycle hooks in a scaling group 6 N/A
SLB instances associated with a scaling group 5 Auto Scaling automatically increases the quota based on your usage. A maximum of 20 SLB instances can be associated with a scaling group.
VServer groups specified when you associate a scaling group with SLB instances 5 N/A
ApsaraDB for RDS instances associated with a scaling group 5 Auto Scaling automatically increases the quota based on your usage. A maximum of 20 ApsaraDB for RDS instances can be associated with a scaling group.
Scheduled tasks within the same region and in the same account 60 Auto Scaling automatically increases the quota based on your usage. A maximum of 140 scheduled tasks can be created per region in an account.
Instance types in a scaling configuration 10 N/A