AWS Certified SysOps Administrator – Associate (legacy) — Question 781

When rebalancing, Auto Scaling launches new instances before terminating the old ones, so that re-balancing does not compromise the performance or availability of your application. Because Auto Scaling attempts to launch new instances before terminating the old ones, being at or near the speci-fied maximum capacity could impede or completely halt rebalancing activities. What does Auto Scaling do in order to avoid this problem?

Answer options

• A. It can temporarily exceed the specified maximum capacity of a group by a 20 percent margin (or by a 2-instance margin, whichever is greater) during a rebalancing activity.
• B. It can add new reserved instances you have defined.
• C. It can temporarily exceed the specified maximum capacity of a group by a 10 percent margin (or by a 1-instance margin, whichever is greater) during a rebalancing activity.
• D. It can temporarily exceed the specified maximum capacity of a group by a 5 percent margin (or by a 1-instance margin, whichever is greater) during a rebalancing activity.

Correct answer: C

Explanation

To maintain application performance and availability during a rebalancing activity, Auto Scaling can temporarily exceed the group's specified maximum capacity by a 10 percent margin (or by 1 instance, whichever is greater). This design prevents the rebalancing process from being blocked when the group is already running at or near its maximum limit. Other percentage thresholds or utilizing reserved instances are incorrect as they do not reflect Auto Scaling's default behavior.