What Is the Expected Number of Instances?

The expected number of instances refers to the number of ECSs that are expected to run in an AS group. It is between the minimum number of instances and the maximum number of instances. You can manually change the expected number of instances or change it based on the scheduled, periodic, or alarm policies.

You can set this parameter when creating an AS group. If this value is greater than 0, a scaling action is performed to add the required number of ECSs after the AS group is created. You can also change this value manually or by scaling policies after the AS group is created.

If you manually change this value, the current number of ECSs is not consistent with the expected number. A scaling action is performed to adjust the number of ECSs to the expected number.

If a scaling policy is triggered to add two ECSs to the AS group, the system will add two to the expected number. Then, a scaling action is performed to add two ECSs so that the number of ECSs in the AS group is the same as the expected number.