For each scaling group, you can control when to add instances to it (scale-out) or remove instances from it (scale-in). You can scale the size of your group manually by adding or removing instances, or you can use scaling policies to let AS automate the process.
When a scaling group automatically scales-in, you need to know which instances should be terminated first. The selection is based on the removal policy.
When scaling-in, you can prevent AS from terminating specific instances by using instance protection.
Removal Policy
When a scaling group is scaled-in, it decides which machine to remove based on the removal policy. You can choose from two removal policies:
- Remove the oldest instances: Delete the earliest added machine.
- Remove the Latest instances: Delete the most recently added machine.
Setting and Modifying Removal Policies in the Console
There are two ways to set it:
- When you create a scaling group, select the removal policy you want.
- On the scaling group details page, click Edit to modify the scaling policy.