Adaptive Adjustment of AWS RI Purchase Targets: A Sigmoid-Based Approach | Blog

Harness has developed a cloud savings strategy that leverages a sigmoid-based approach to optimize the purchasing of AWS Reserved Instances (RIs). By automating the buying process, the aim is to achieve significant cost savings without overcommitting resources. The previous system triggered abrupt changes in purchasing behavior, resulting in inefficiencies. To address this, Harness implemented a sigmoid function to adjust purchase targets dynamically, ensuring a smooth transition as the target coverage is approached. This method enables aggressive purchasing at lower coverage levels and gradual reduction as the target nears, preventing overspending and enhancing predictability. The adoption of this approach has led to a 5-10% increase in cloud savings and more stable purchasing patterns. Future enhancements may include dynamic smoothing factors and customer-specific tuning to further optimize cost management.