Hands-On LLM Serving and Optimization

Chapter 3. Model Serving System Design: A Deep Dive

In Chapter 1, we introduced the major model serving paradigms, outlining common architectural patterns and trade-offs. In Chapter 2, we examined how LLMs perform inference and generate text at the model level. This chapter bridges those foundations to production engineering: how to organize code and infrastructure to construct complete serving systems for both single-model and multi-model scenarios.

Model serving is a rapidly evolving field, with hundreds of open source serving frameworks and commercial solutions available. Evaluating, adopting, and customizing the right solution can quickly become overwhelming. Rather than starting with a specific framework, we focus in this chapter on building intuition from first principles. By understanding how serving systems are structured at a fundamental level, you’ll be better equipped to reason about any framework or managed service.

To that end, we develop two simplified yet representative serving systems: one for single-model LLM serving and one for multi-model serving. These implementations are intentionally streamlined—they are not meant to replace production frameworks like Triton or vLLM—but they capture the core components and architectural decisions that define real-world systems. Through these examples, you will see how batching, streaming, routing, isolation, and resource management fit together in practice.

We begin by constructing a single-model LLM serving service that ...