CoreTrail

Traditional ML serving vs LLM serving

The deployment fundamentals survive. The expensive resource, request shape, and useful scaling signals change.

Core 3 min read
On this page

A traditional online model can often be thought of as:

features → forward pass → prediction.

An autoregressive large language model (LLM) still runs inference behind an application programming interface (API), but one request remains active through prompt processing and many decode steps while retaining per-request attention state.

What stays the same

Both systems still need familiar production concerns:

  • a versioned model artifact;
  • repeatable deployment;
  • request validation and authentication;
  • load balancing and replicas;
  • health checks;
  • rollouts and rollback;
  • metrics, logs, and traces;
  • capacity planning and cost control.

Docker and Kubernetes keep the same responsibilities whether the workload is a web application, a conventional model, or an LLM server.

What changes enough to affect the architecture

Traditional ML serving LLM serving
Often one bounded forward pass Prefill followed by autoregressive decode
Often smaller and easier to place; size varies widely by model family Large checkpoints can reach tens or hundreds of gigabytes
Central processing unit (CPU) serving is common for many models Graphics processing unit (GPU) / accelerator serving is common
Per-request state is often small Active sequences retain key-value (KV) cache state
Request cost is often relatively predictable Prompt/output token lengths vary widely
Ordinary/dynamic batching Continuous batching across active sequences
Replica often maps simply to one process/device One logical replica may span several GPUs/nodes
CPU and requests per second (RPS) can be useful scaling signals Queue depth, time to first token (TTFT), KV pressure, token throughput become important
Startup can be quick Weight transfer/loading/warmup can dominate scale-out

Same system-design fundamentals, different bottlenecks

A queue is still a queue. Replication is still replication. Backpressure is still backpressure.

The difference is what saturates.

For a web or prediction API, you may hit CPU, memory, database connections, or I/O.

For an LLM serving replica, the constraint may be:

GPU compute
GPU memory
KV-cache capacity
token throughput
inter-GPU communication
model startup time

An autoscaling rule such as “scale at 70% CPU utilization” can miss queue or memory pressure in an LLM service even though horizontal scaling remains the right general mechanism.

MLOps still owns the model lifecycle

Machine learning operations (MLOps) still covers model registries, versioning, deployment promotion, evaluation gates, monitoring, and rollback.

LLM serving adds token-generation, memory, and concurrency constraints on top of that lifecycle.

Continue with LLM inference for the execution details or Infrastructure & DevOps for the reusable deployment mechanics.

References

Type a concept, keyword, or function.