AWS DevOps Engineer Professional Practice Test

Which AWS service helps applications automatically scale in and out based on demand?

1. AWS Elastic Load Balancing

2. AWS Auto Scaling

3. AWS CloudFormation

4. AWS Step Functions

The correct answer is: AWS Auto Scaling

AWS Auto Scaling is specifically designed to help applications automatically scale in and out based on demand. This service monitors your application's performance and adjusts the number of instances running based on real-time performance metrics and defined scaling policies. It ensures optimal performance and cost-effectiveness by automatically increasing the number of instances during peak usage times and decreasing them during low demand periods. In contrast, AWS Elastic Load Balancing helps distribute incoming application traffic across multiple targets, such as Amazon EC2 instances, but it does not directly scale these instances. AWS CloudFormation is a service used to define and provision AWS infrastructure as code, but it does not have built-in auto-scaling capabilities. AWS Step Functions enables you to coordinate multiple AWS services into serverless workflows, facilitating the building of complex applications, but it also does not handle scaling based on demand. Thus, AWS Auto Scaling is the clear choice for automatically managing the scaling of application resources.