Design and Implementation of Ctrip's Soft Load Balancer: Evolving from Nginx Reverse Proxy to an OpenResty‑Based API Gateway
This article details how Ctrip's Soft Load Balancer (SLB) transitioned from a simple Nginx reverse‑proxy to a multi‑datacenter, dynamic routing gateway using OpenResty, Lua scripts, and a three‑layer architecture that eliminates reloads and supports high‑frequency configuration updates.