What’s new with Robinhood, our in-house load balancing service

This post details the latest iteration of Dropbox's internal load balancing service, Robinhood. Key technical contributions include the integration of PID controllers for more effective load management, leading to improved reliability and significant hardware cost savings. The post also elaborates on the architecture, including the load balancing service (LBS), proxy, and routing database (ZooKeeper/etcd-based). It details strategies for handling LBS restarts, cold start nodes, and missing load reports, and supports load balancing based on CPU utilization and/or in-flight requests. Cross-data center routing considerations and locality configuration are also discussed.