Configuring an Instance Removal Policy

When your AS group automatically removes instances, check whether the load between AZs is significantly different. If the number of instances in an AZ is greater than the number of instances in other AZs used by the AS group, AS attempts to balance load between AZs when removing an instance. If the load between AZs is balanced, AS removes instances following the pre-configured instance removal policy.

AS supports the following instance removal policies:

• Oldest instance created from oldest AS configuration: The oldest instance created based on the oldest configuration is removed from the AS group first. Use this policy if you want to update an AS group and delete the instances created based on early AS configurations gradually.
• Newest instance created from oldest AS configuration: The latest instance created based on the oldest configuration is removed from the AS group first.
• Oldest instance: The oldest instance is removed from the AS group first. Use this policy if you want to replace old instances by new instances in an AS group.
• Newest instance: The latest instance is removed from the AS group first. Use this policy if you want to test a new AS configuration and do not want to retain it.

NOTE:

A manually added instance is removed in the lowest priority. AS does not delete a manually added instance when removing it. If multiple manually added instances must be removed, AS preferentially removes the earliest-added instance.