Definition
An Auto Scaling group, often abbreviated as ASG, is a cloud computing service that automatically adjusts the number of compute resources, like virtual servers, to match demand. It works by monitoring application performance metrics and launching or terminating instances based on predefined policies. This ensures applications remain available and performant during peak loads while minimizing costs during periods of low usage. For instance, an e-commerce website might use an ASG to add more web servers during a holiday sale to handle increased customer traffic. Unlike manual scaling, which requires human intervention, ASGs operate autonomously to maintain desired capacity. This concept is frequently tested on AWS certification exams such as the AWS Certified Solutions Architect Associate and cloud security certifications.