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# LLM Deployment Examples using TensorRT-LLM

This directory contains examples and reference implementations for deploying Large Language Models (LLMs) in various configurations using TensorRT-LLM.


## Deployment Architectures

See [deployment architectures](../llm/README.md#deployment-architectures) to learn about the general idea of the architecture.
Note that this TensorRT-LLM version does not support all the options yet.

Note: TensorRT-LLM disaggregation does not support conditional disaggregation yet. You can only configure the deployment to always use aggregate or disaggregated serving.

## Getting Started

1. Choose a deployment architecture based on your requirements
2. Configure the components as needed
3. Deploy using the provided scripts

### Prerequisites

Start required services (etcd and NATS) using [Docker Compose](../../deploy/docker-compose.yml)
```bash
docker compose -f deploy/docker-compose.yml up -d
```

### Build docker

#### Step 1: Build TensorRT-LLM base container image

Because of the known issue of C++11 ABI compatibility within the NGC pytorch container, we rebuild TensorRT-LLM from source.
See [here](https://nvidia.github.io/TensorRT-LLM/installation/linux.html) for more informantion.

Use the helper script to build a TensorRT-LLM container base image. The script uses a specific commit id from TensorRT-LLM main branch.

```bash
# TensorRT-LLM uses git-lfs, which needs to be installed in advance.
apt-get update && apt-get -y install git git-lfs

# The script uses python packages like docker-squash to squash image
# layers within trtllm base image
DEBIAN_FRONTEND=noninteractive TZ=America/Los_Angeles apt-get -y install python3 python3-pip python3-venv

./container/build_trtllm_base_image.sh
```

For more information see [here](https://nvidia.github.io/TensorRT-LLM/installation/build-from-source-linux.html#option-1-build-tensorrt-llm-in-one-step) for more details on building from source.
If you already have a TensorRT-LLM container image, you can skip this step.

#### Step 2: Build the Dynamo container

```
# On an x86 machine:
./container/build.sh --framework tensorrtllm

# On an ARM machine:
./container/build.sh --framework tensorrtllm --platform linux/arm64
```

This build script internally points to the base container image built with step 1. If you skipped previous step because you already have the container image available, you can run the build script with that image as a base.


```bash
# Build dynamo image with other TRTLLM base image.
./container/build.sh --framework TENSORRTLLM --base-image <trtllm-base-image> --base-image-tag <trtllm-base-image-tag>
```

### Run container

```
./container/run.sh --framework tensorrtllm -it
```
## Run Deployment

This figure shows an overview of the major components to deploy:



```

+------+      +-----------+      +------------------+             +---------------+
| HTTP |----->| processor |----->|      Worker      |------------>|     Prefill   |
|      |<-----|           |<-----|                  |<------------|     Worker    |
+------+      +-----------+      +------------------+             +---------------+
                  |    ^                  |
       query best |    | return           | publish kv events
           worker |    | worker_id        v
                  |    |         +------------------+
                  |    +---------|     kv-router    |
                  +------------->|                  |
                                 +------------------+

```

Note: The above architecture illustrates all the components. The final components
that get spawned depend upon the chosen graph.

### Example architectures

#### Aggregated serving
```bash
cd /workspace/examples/tensorrt_llm
dynamo serve graphs.agg:Frontend -f ./configs/agg.yaml
```

#### Aggregated serving with KV Routing
```bash
cd /workspace/examples/tensorrt_llm
dynamo serve graphs.agg_router:Frontend -f ./configs/agg_router.yaml
```

#### Disaggregated serving
```bash
cd /workspace/examples/tensorrt_llm
dynamo serve graphs.disagg:Frontend -f ./configs/disagg.yaml
```

We are defining TRTLLM_USE_UCX_KVCACHE so that TRTLLM uses UCX for transfering the KV
cache between the context and generation workers.

#### Disaggregated serving with KV Routing
```bash
cd /workspace/examples/tensorrt_llm
dynamo serve graphs.disagg_router:Frontend -f ./configs/disagg_router.yaml
```

We are defining TRTLLM_USE_UCX_KVCACHE so that TRTLLM uses UCX for transfering the KV
cache between the context and generation workers.

#### Multi-Node Disaggregated Serving

In the following example, we will demonstrate how to run a Disaggregated Serving
deployment across multiple nodes. For simplicity, we will demonstrate how to
deploy a single Decode worker on one node, and a single Prefill worker on the other node.
However, the instance counts, TP sizes, other configs, and responsibilities of each node
can be customized and deployed in similar ways.

##### Head Node

Start nats/etcd:
```bash
# NATS data persisted to /tmp/nats/jetstream by default
nats-server -js &

# Persist data to /tmp/etcd, otherwise defaults to ${PWD}/default.etcd if left unspecified
etcd --listen-client-urls http://0.0.0.0:2379 --advertise-client-urls http://0.0.0.0:2379 --data-dir /tmp/etcd &

# NOTE: Clearing out the etcd and nats jetstream data directories across runs
#       helps to guarantee a clean and reproducible results.
```

Launch graph of Frontend, Processor, and TensorRTLLMWorker (decode) on head node:

```bash
cd /workspace/examples/tensorrt_llm
dynamo serve graphs.agg:Frontend -f ./configs/disagg.yaml &
```

Notes:
- The aggregated graph (`graphs.agg`) is chosen here because it also describes
  our desired deployment settings for the head node: launching the utility components
  (Frontend, Processor), and only the decode worker (TensorRTLLMWorker configured with
  `remote-prefill` enabled). We plan to launch the `TensorRTLLMPrefillWorker`
  independently on a separate node in the next step of this demonstration.
  You are free to customize the graph and configuration of components launched on
  each node.
- The disaggregated config `configs/disagg.yaml` is intentionally chosen here as a
  single source of truth to be used for deployments on all of our nodes, describing
  the configurations for all of our components, including both decode and prefill
  workers, but can be customized based on your deployment needs.

##### Worker Node(s)

Set environment variables pointing at the etcd/nats endpoints on the head node
so the Dynamo Distributed Runtime can orchestrate communication and
discoverability between the head node and worker nodes:
```bash
# if not head node
export HEAD_NODE_IP="<head-node-ip>"
export NATS_SERVER="nats://${HEAD_NODE_IP}:4222"
export ETCD_ENDPOINTS="${HEAD_NODE_IP}:2379"
```

Deploy a Prefill worker:
```
cd /workspace/examples/tensorrt_llm
dynamo serve components.prefill_worker:TensorRTLLMPrefillWorker -f ./configs/disagg.yaml --service-name TensorRTLLMPrefillWorker &
```

Now you have a 2-node deployment with 1 Decode worker on the head node, and 1 Prefill worker on a worker node!

##### Additional Notes for Multi-Node Deployments

Notes:
- To include a router in this deployment, change the graph to one that includes the router, such as `graphs.agg_router`,
  and change the config to one that includes the router, such as `configs/disagg_router.yaml`
- This step is assuming you're disaggregated serving and planning to launch prefill workers on separate nodes.
  Howerver, for an aggregated deployment with additional aggregated worker replicas on other nodes, this step
  remains mostly the same. The primary difference between aggregation and disaggregation for this step is
  whether or not the `TensorRTLLMWorker` is configured to do `remote-prefill` or not in the config file
  (ex: `configs/disagg.yaml` vs `configs/agg.yaml`).
- To apply the same concept for launching additional decode workers on worker nodes, you can
  directly start them, similar to the prefill worker step above:
  ```bash
  # Example: deploy decode worker only
  cd /workspace/examples/tensorrt_llm
  dynamo serve components.worker:TensorRTLLMWorker -f ./configs/disagg.yaml --service-name TensorRTLLMWorker &
  ```

### Client

See [client](../llm/README.md#client) section to learn how to send request to the deployment.

NOTE: To send a request to a multi-node deployment, target the node which deployed the `Frontend` component.

### Close deployment

See [close deployment](../../docs/guides/dynamo_serve.md#close-deployment) section to learn about how to close the deployment.

### Benchmarking

To benchmark your deployment with GenAI-Perf, see this utility script, configuring the
`model` name and `host` based on your deployment: [perf.sh](../llm/benchmarks/perf.sh)

### Future Work

Remaining tasks:
- [x] Add support for the disaggregated serving.
- [x] Add multi-node support.
- [x] Add instructions for benchmarking.
- [ ] Add integration test coverage.
- [ ] Merge the code base with llm example to reduce the code duplication.
- [ ] Use processor from dynamo-llm framework.
- [ ] Enable NIXL integration with TensorRT-LLM once available. Currently, TensorRT-LLM uses UCX to transfer KV cache.
