Auto Scaling dynamically adjusts computing resources based on policies but has feature and resource limits. For example, each scaling operation has a maximum number of Elastic Compute Service (ECS) instances. This topic describes these restrictions.
Limits on features
Auto Scaling features have the following limits:
Apps on ECS instances or elastic container instances in a scaling group must be stateless and horizontally scalable.
Avoid storing session data, app data, or logs on ECS instances or elastic container instances in scaling groups, as they may be automatically released. For persistent storage, use independent instances for sessions, ApsaraDB RDS for app data, and Simple Log Service for logs. For more information, see What is ApsaraDB RDS? and What is Simple Log Service?
Auto Scaling can't update ApsaraDB for Memcache whitelists. Therefore , you must add private IP addesses manually. For more information, see Configure an IP address whitelist.
Auto Scaling automatically detaches deleted resources, such as ApsaraDB RDS instances, Application Load Balancer (ALB) instances, Classic Load Balancer (CLB) instances, or CLB backend server groups, from scaling groups.
Auto Scaling disables automatic scaling after 30 consecutive days of failed operations and alerts users via text message or email.
ImportantIf a scaling operation fails consecutively, we recommend that you log on to the Auto Scaling console to resolve the issue.
Limits on resources
The following table describes the Auto Scaling resource limits per Alibaba Cloud account.
Resource | Quota |
Maximum number of scaling groups allowed in a region | To view the quota, visit Quota Center. Note You can submit a ticket to request a quota increase. |
Maximum number of scaling configurations allowed in a scaling group | |
Maximum number of scaling rules allowed in a scaling group | |
Maximum number of ApsaraDB RDS instances that can be associated with a scaling group | |
Maximum number of CLB instances that can be associated with a scaling group | |
Maximum number of ALB server groups that can be associated with a scaling group | |
Maximum number of Network Load Balancer (NLB) server groups that can be associated with a scaling group | |
Maximum number of vServer groups that can be associated with a scaling group | |
Maximum number of instances allowed in a scaling group | |
Maximum number of scheduled tasks allowed in a region | |
Maximum number of ECS instances or elastic container instances that can be scaled at a time | 1000 |
Maximum number of instance types allowed in a scaling configuration | 10 |
Maximum number of notification rules allowed in a scaling group | 6 |
Maximum number of lifecycle hooks allowed in a scaling group | 10 |