GPU and TPU utilization with multi-cluster GKE Inference Gateway

Demand for AI infrastructure is at an all-time high. Global accelerator shortages mean engineering teams can rarely get all the compute they need from just one data center — capacity comes a cluster here, a cluster there, often an ocean apart. At the same time, workloads are getting hungrier: Today’s long-running agentic workloads often have context windows of 100k to 800k+ tokens, which consume accelerator memory faster than any previous generation of AI traffic.

In this environment, the goal is to maximize “intelligence per dollar.” Fragmented, poorly balanced infrastructure is rarely up to the task though, allowing expensive accelerators to sit idle, while requests queue up somewhere else.

To close that gap, we built a layered routing architecture that makes globally scattered capacity behave like a single pool behind a single entry point. At the edge, the multi-cluster GKE Inference Gateway focuses on global, multi-region traffic distribution and high availability. Beneath that, the LLM-d router handles the complex, memory-aware scheduling algorithms that keep utilization high. 

This architecture is deliberately runtime-, model-, and accelerator-agnostic — it works across serving frameworks, model families, and GPU or TPU hardware. To make the results concrete rather than abstract, we recently benchmarked managing production-level global request routing at scale across a multi-region GKE deployment of 17,000 compute nodes spread across the US and Europe. The deployment served a leading Mixture of Experts (MoE) foundation model using SGLang. 

The results: Scaling to three clusters achieved a near-linear throughput boost while maintaining a 99.9% success rate under heavy multi-client concurrency. Additionally, routing traffic through the multi-cluster GKE Inference Gateway added less than 1% overhead, delivering 99.5% of the throughput of a direct, local cluster call.

Read on to learn how it works, more on the benchmark results, and what it means for your own distributed inference deployment.

Three regions, one endpoint

The deployment spanned three GKE clusters in three geographic regions: us-east5 (the config cluster), us-west8, and europe-west4. However, from the client’s perspective, none of that geography exists. Requests hit a single global virtual IP, and the gateway decides — in real time — which cluster should serve each one. 

What makes that decision smart rather than blind is telemetry. Instead of traditional round-robin routing at the network layer, the multi-cluster load balancer is configured to route traffic based on live application signals. Specifically, the Endpoint Picker Proxy (EPP) reads the KV-cache token utilization natively exposed by the underlying inference engines and emits it as a metric for the load balancer. When the load balancer sees a region running hot based on this emitted metric, it spills traffic to the next healthy region.