For each scaling group, you can set the time for adding (scale-out) or removing (scale-in) instances. You can scale the scaling group manually by adding or removing instances, or you can enable AS to execute this process automatically by using a scaling policy.
Note:
When a scaling group is scaled in automatically, it needs to know which instances should be terminated first, and the selection is based on the removal policy.
During scale-in, you can prevent specified instances from being terminated by AS by using instance protection.
For a scaling group configured with a CLB instance, when the instances are automatically or manually removed or deleted, they will be automatically disassociated from the CLB instance.
Removal policy
AS will determine which CVM should be removed based on the removal policy during scale-in. You can choose from the following two removal policies:
Remove the oldest instances: Remove earliest CVM instances added to the scaling group.
Remove the latest instances: Remove latest CVM instances added to the scaling group.
Note:
CVM instances that added within the same second will be randomly selected without an accurate order.
Setting and modifying removal policy in the console
There are two ways to set this up:
Select the removal policy you want when creating the scaling group.
On the Scaling Group Details page, click Edit to modify the scaling policy.