name: vllm-plugin-fl-setup-flagos
description: >
Install and configure vLLM-Plugin-FL for multiple hardware backends including NVIDIA, Ascend
and etc. Use when setting up vllm-plugin-fl, configuring the environment for specific hardware
backend, installing dependencies, checking whether dependencies are installed successfully,
resolving runtime issues, and launching inference to verify successful model serving. Trigger
when the user says things like "setup vllm-plugin-fl", "install vllm-plugin-fl",
"configure FL plugin", "set up FlagGems", or "set up FlagCX".
argument-hint: "[backend]"
user-invocable: false
compatibility: "Linux (Ubuntu 20.04+), Python 3.10+, vLLM v0.13.0, GPU with appropriate drivers"
metadata:
version: "1.0.0"
author: flagos-ai
category: environment-setup
tags: [vllm, vllm-plugin-fl, flaggems, flagcx, setup, installation]

vLLM-Plugin-FL Setup

Overview

vLLM-Plugin-FL extends vLLM to support model inference/serving across diverse hardware backends (NVIDIA, Ascend, MetaX, Iluvatar, etc.) via FlagOS's unified operator library FlagGems and communication library FlagCX. This skill covers installation, hardware-specific environment configuration, and dependency setup.

Prerequisites

• Linux OS (Ubuntu 20.04+ recommended)
• Python 3.10+
• vLLM v0.13.0 — install from the official v0.13.0 release or the fork vllm-FL
• GPU with appropriate drivers (NVIDIA CUDA, Huawei Ascend, etc.)
• pip package manager
• Git

Verify vLLM version before proceeding:

python -c "import vllm; print(vllm.__version__)"
# Expected output: 0.13.0

Installation Workflow

Step 1: Identify Hardware Backend

# NVIDIA GPU
nvidia-smi

# Huawei NPU
npu-smi info

# Moore Threads GPU
mthreads-gmi

# Iluvatar GPU
ixsmi

Step 2: Install vLLM-Plugin-FL

First create a workspace directory and try cloning the source code:

mkdir -p ~/flagos-workspace && cd ~/flagos-workspace
git clone https://github.com/flagos-ai/vllm-plugin-FL

If git clone fails due to network issues, ask the user for their network proxy settings (e.g. http_proxy / https_proxy), configure the proxy, then retry the clone.

Then install from the source directory:

cd vllm-plugin-FL
pip install -r requirements.txt
pip install --no-build-isolation .
# Required to enable vLLM-Plugin-FL when running vLLM
export VLLM_PLUGINS='fl'

Verify vLLM-Plugin-FL installation:

python -c "import vllm_fl; print('vllm-plugin-FL installed successfully')"

Step 3: Install FlagGems

Ascend NPU users: Before installing FlagGems, you must first install FlagTree. See references/npu.md and complete the FlagTree installation step there before proceeding. Otherwise the FlagGems verification will fail repeatedly and keep reinstalling Triton.

# Install build dependencies
pip install -U scikit-build-core==0.11 pybind11 ninja cmake

# Clone FlagGems source code
cd ~/flagos-workspace
git clone https://github.com/flagos-ai/FlagGems

If git clone fails due to network issues, ask the user for their network proxy settings (e.g. http_proxy / https_proxy), configure the proxy, then retry the clone.

Then install from the source directory:

cd FlagGems
pip install --no-build-isolation .

Verify FlagGems installation:

python -c "import flag_gems; print('FlagGems installed successfully')"

Step 4: (Optional) Install FlagCX

FlagCX is a unified communication library for multi-device distributed inference, supporting both homogeneous and heterogeneous setups. Skip this step if running on a single device.

Note: Ascend NPU does not need FlagCX — skip this step for Ascend backends.

cd ~/flagos-workspace
git clone https://github.com/flagos-ai/FlagCX.git

If git clone fails due to network issues, ask the user for their network proxy settings (e.g. http_proxy / https_proxy), configure the proxy, then retry the clone.

Then build and install from the source directory:

cd FlagCX

git submodule update --init --recursive

# Build for your platform (e.g. USE_NVIDIA=1 for NVIDIA)
make USE_NVIDIA=1

export FLAGCX_PATH="$PWD"

# Install Python binding (replace [xxx] with your platform: nvidia, ascend, etc.)
cd plugin/torch/
FLAGCX_ADAPTOR=[xxx] pip install --no-build-isolation .

Verify FlagCX installation:

python -c "import flagcx; print('FlagCX installed successfully')"

Step 5: Backend-Specific Setup

Some hardware backends require additional setup. See the corresponding reference document:

| Backend | Chip Vendor | Reference |
|---------|-------------|-----------|
| Ascend NPU | Huawei | references/npu.md |
| MetaX GPU | MetaX | TBD |
| Iluvatar GPU (BI-V150) | Iluvatar | references/iluvatar<em>gpu.md |
| Pingtouge-Zhenwu | Pingtouge | TBD |
| Tsingmicro | Tsingmicro | TBD |
| Moore Threads GPU | Moore Threads | references/mthreads<em>gpu.md |
| Hygon DCU | Hygon | TBD |

Quick Test

1. Ask the user for the model name they want to test (e.g. Qwen3-4B, DeepSeek-R1).
2. Search the machine for a local copy of that model:

   find / -maxdepth 5 -type d -name "<user_provided_model_name>" 2>/dev/null

1. If found, use the discovered path. If not found, tell the user and ask them to provide a different model name or a full local path, then repeat the search. If after 3 attempts no valid model is found, skip the quick test and inform the user to prepare a model before retrying.
2. Ensure the FL plugin is enabled before running inference:

   export VLLM_PLUGINS='fl'

For Moore Threads GPU, also set:

   export USE_FLAGGEMS=1
   export FLAGCX_PATH=/workspace/FlagCX  # MUST point to the actual FlagCX installation directory; this is only an example
   export VLLM_MUSA_ENABLE_MOE_TRITON=1

1. Once a valid model path is resolved, run offline batched inference to verify the full stack:

from vllm import LLM, SamplingParams

model_path = "<resolved_model_path>"
prompts = [
    "Hello, my name is",
]
sampling_params = SamplingParams(max_tokens=10, temperature=0.0)

# For Moore Threads GPU, add: enforce_eager=True, block_size=64, attention_config={"backend": "TORCH_SDPA"}
# For Iluvatar BI-V150, add: enforce_eager=True
llm = LLM(model=model_path, max_num_batched_tokens=16384, max_num_seqs=2048)
outputs = llm.generate(prompts, sampling_params)
for output in outputs:
    prompt = output.prompt
    generated_text = output.outputs[0].text
    print(f"Prompt: {prompt!r}, Generated text: {generated_text!r}")

Troubleshooting

Out of memory on model load: Use gpu_memory_utilization parameter to limit memory. Start with 0.8 and adjust:

from vllm import LLM
llm = LLM(model="...", gpu_memory_utilization=0.8)

FlagGems build failures: Ensure build dependencies are installed (scikit-build-core, pybind11, ninja, cmake). Check that your compiler supports C++17.

Plugin not loaded: If vLLM does not use the FL plugin, verify that VLLM_PLUGINS='fl' is set in your environment.

FlagCX communication errors: Ensure FLAGCX_PATH is correctly set and the library was built for your platform. For NVIDIA, verify with make USE_NVIDIA=1.

Ascend-specific issues: See references/npu.md for Ascend NPU troubleshooting, including FlagTree setup and eager execution requirements.

Cannot connect to GitHub: Ask the user for their network proxy settings (e.g. http_proxy / https_proxy), configure the proxy, then retry the git clone command.

References

• vLLM-Plugin-FL GitHub
• FlagGems GitHub
• FlagCX GitHub
• For non-NVIDIA chips, refer to the references directory for hardware-specific configurations and setup instructions