Intelligent Kubernetes Load Balancing
You're running gRPC services in Kubernetes, load balancing looks fine on the dashboard — but some pods are burning at 80% CPU while others sit idle, and adding more replicas only partially helps.
Rohit Agrawal, a Staff Software Engineer on the traffic platform team at Databricks, explains why this happens and how his team replaced Kubernetes's default networking with a proxy-less, client-side load-balancing system built on the xDS protocol.
In this episode:
- Why KubeProxy's Layer 4 routing breaks down under high-throughput gRPC: it picks a backend once per TCP connection, not per request
- How Databricks built an Endpoint Discovery Service (EDS) that watches Kubernetes directly and streams real-time pod metadata to every client
- How zone-aware spillover cut cross-availability-zone costs without sacrificing availability
- Why CPU-based routing failed (monitoring lag creates oscillation) and what signals to use instead
The system has been running in production for three years across hundreds of services, handling millions of requests.
