This topic lists the limits of Resource Orchestration Service (ROS).

Item Limit
The maximum number of stacks allowed to be created by an Alibaba Cloud account. 200
The maximum number of templates allowed to be created by an Alibaba Cloud account. 100
The maximum number of stack groups allowed to be created by an Alibaba Cloud account. 100
The maximum number of instances allowed to be created in a stack group by an Alibaba Cloud account. 2,000
The maximum number of concurrent operations allowed to be performed on stack groups within a region by an Alibaba Cloud account. 3,500
The maximum number of change sets allowed to be created in a stack by an Alibaba Cloud account. 20
The maximum number of resources allowed to be created in a stack. 200
The maximum number of levels that a nested stack is allowed to contain. 5
The maximum timeout period of a stack. 1,440 minutes (or 24 hours)
The minimum timeout period of a stack. 10 minutes
The maximum size of a template file. 512KB
The maximum size of a custom resource response. 4,096KB
The maximum size of a change set file. 2,048KB
The maximum size of a stack policy file. 16KB