Auto Scaling
Definition
Auto scaling is a cloud computing capability that automatically adjusts the number of computational resources allocated to an application or service based on observed demand.
This mechanism is central to managing fluctuating workloads efficiently within cloud environments. It functions by continuously monitoring predefined performance metrics, such as CPU utilization, network traffic, or request queue length, to determine when to dynamically add or remove resources. The goal is to ensure consistent application performance and availability while optimizing operational costs.
When demand for a service increases beyond a specified threshold, auto scaling "scales out" by automatically provisioning and launching new instances, containers, or other compute units to handle the elevated load. Conversely, when demand recedes, it "scales in" by automatically terminating underutilized resources. This prevents performance degradation during peak usage and avoids unnecessary expenditures on idle resources during off-peak periods.
For example, an e-commerce website might use auto scaling to automatically increase its web server capacity during a holiday sale and then reduce it once the sale concludes. This feature is commonly deployed in contexts such as web applications, APIs, microservices architectures, and data processing systems hosted on public or private cloud infrastructures.