Opportunities and Challenges in Service Layer Traffic Engineering

Optimizing request routing in large microservice-based applications is difficult, especially when applications span multiple geo-distributed clusters. In this paper, inspired by ideas from network traffic engineering, we propose Service Layer Traffic Engineering (SLATE), a new framework for request routing in microservices that span multiple clusters. SLATE leverages global knowledge of cluster states and multi-hop application graphs to centrally control the flow of requests in order to optimize end-to-end application latency and cost. Realizing such a system requires tackling several technical challenges unique to service layer, such as accounting for different request traffic classes, multi-hop call trees, and application latency profiles. We identify such challenges and build a preliminary prototype that addresses some of them. Preliminary evaluations of our prototype show how SLATE outperforms the state-of-the-art global load balancing approach (used by Meta's Service Router and Google's Traffic Director) by up to 3.5× in average latency and reduces egress bandwidth cost by up to 11.6×.