AWS Certified Solutions Architect Associate Test 10

Auto Scaling enables you to follow the demand curve for your applications closely, reducing the needto manually provision Amazon EC2 capacity in advance. For example, you can set a condition to addnew Amazon EC2 instances in increments to the Auto Scaling group when the average utilization ofyour Amazon EC2 fleet is high; and similarly, you can set a condition to remove instances in the sameincrements when CPU utilization is low. If you have predictable load changes, you can set a schedulethrough Auto Scaling to plan your scaling activities. You can use Amazon CloudWatch to send alarmsto trigger scaling activities and Elastic Load Balancing to help distribute traffic to your instanceswithin Auto Scaling groups. Auto Scaling enables you to run your Amazon EC2 fleet at optimalutilization.

Reference: http://aws.amazon.com/autoscaling/