Use Restrictions

AS has the following restrictions:

• Only applications that are stateless and can be horizontally scaled can run on instances in an AS group.
  

  • A stateless process or application can be understood in isolation. There is no stored knowledge of or reference to past transactions. Each transaction is made as if from scratch for the first time.

    ECSs where are stateless applications running do not store data that needs to be persisted locally.

    Think of stateless transactions as a vending machine: a single request and a response.

  • Stateful applications and processes, however, are those that can be returned to again and again. They are performed with the context of previous transactions and the current transaction may be affected by what happened during previous transactions.

    ECSs where stateful applications are running store data that needs to be persisted locally.

    You can think of stateful transactions as online banking or e-mail, which are performed with the context of previous transactions.

• AS automatically releases ECS instances. Therefore, the instances in AS groups cannot be used to save application status information (such as session statuses) and related data (such as database data and logs). If the application status or related data must be saved, you can store the information on separate servers.
• AS does not support capacity expansion or deduction of instance vCPUs and memory.
• AS resources must comply with quota requirements listed in Table 1.

  Table 1 Quota list

  Category	Description	Default Value
  AS group	Maximum number of AS groups that you can create	10
  AS configuration	Maximum number of AS configurations that you can create	100
  AS policy	Maximum number of AS policies that can be added to an AS group	10
  Instance	Maximum number of instances that can be added to an AS group	300
  Bandwidth scaling policy	Maximum number of bandwidth scaling policies that you can create	10