AWS DevOps Engineer Professional Practice Test 2025 - Free DevOps Practice Questions and Certification Study Guide

The lifecycle events associated with Auto Scaling Groups during a Scale-Out operation are indeed "Pending" events, which include the actions "Wait" and "Proceed." When an Auto Scaling group scales out, it launches new instances to meet increased demand. The "Pending" lifecycle state indicates that the new instances are in the process of being created and initialized before they become available for use.

During this process, the "Wait" action allows the Auto Scaling system to pause and allow time for the new instances to initialize properly, and once they are ready, the "Proceed" action is invoked to indicate that these instances are now available to handle application load. This two-step process ensures that the instances are fully operational before they start receiving traffic, which is crucial for maintaining application performance and stability.

The other options represent lifecycle events that do not pertain to the Scale-Out operation. For instance, "Terminating" events are associated with the process of removing instances, while "Scaling" and "Ready" do not reflect the specific actions and states involved in adding new resources like "Pending" does in the context of a scale-out event.