sgl-project--sglang/docs/references/multi_node_deployment/multi_node.md

Multi-Node Deployment

Llama 3.1 405B

Run 405B (fp16) on Two Nodes

# replace 172.16.4.52:20000 with your own node ip address and port of the first node

python3 -m sglang.launch_server \
  --model-path meta-llama/Meta-Llama-3.1-405B-Instruct \
  --tp 16 \
  --dist-init-addr 172.16.4.52:20000 \
  --nnodes 2 \
  --node-rank 0

python3 -m sglang.launch_server \
  --model-path meta-llama/Meta-Llama-3.1-405B-Instruct \
  --tp 16 \
  --dist-init-addr 172.16.4.52:20000 \
  --nnodes 2 \
  --node-rank 1

Note that LLama 405B (fp8) can also be launched on a single node.

python -m sglang.launch_server --model-path meta-llama/Meta-Llama-3.1-405B-Instruct-FP8 --tp 8

DeepSeek V3/R1

Please refer to DeepSeek documents for reference.

Multi-Node Inference on SLURM

This example showcases how to serve SGLang server across multiple nodes by SLURM. Submit the following job to the SLURM cluster.

#!/bin/bash -l

#SBATCH -o SLURM_Logs/%x_%j_master.out
#SBATCH -e SLURM_Logs/%x_%j_master.err
#SBATCH -D ./
#SBATCH -J Llama-405B-Online-Inference-TP16-SGL

#SBATCH --nodes=2
#SBATCH --ntasks=2
#SBATCH --ntasks-per-node=1  # Ensure 1 task per node
#SBATCH --cpus-per-task=18
#SBATCH --mem=224GB
#SBATCH --partition="lmsys.org"
#SBATCH --gres=gpu:8
#SBATCH --time=12:00:00

echo "[INFO] Activating environment on node $SLURM_PROCID"
if ! source ENV_FOLDER/bin/activate; then
    echo "[ERROR] Failed to activate environment" >&2
    exit 1
fi

# Define parameters
model=MODEL_PATH
tp_size=16

echo "[INFO] Running inference"
echo "[INFO] Model: $model"
echo "[INFO] TP Size: $tp_size"

# Set NCCL initialization address using the hostname of the head node
HEAD_NODE=$(scontrol show hostname "$SLURM_NODELIST" | head -n 1)
NCCL_INIT_ADDR="${HEAD_NODE}:8000"
echo "[INFO] NCCL_INIT_ADDR: $NCCL_INIT_ADDR"

# Launch the model server on each node using SLURM
srun --ntasks=2 --nodes=2 --output="SLURM_Logs/%x_%j_node$SLURM_NODEID.out" \
    --error="SLURM_Logs/%x_%j_node$SLURM_NODEID.err" \
    python3 -m sglang.launch_server \
    --model-path "$model" \
    --grammar-backend "xgrammar" \
    --tp "$tp_size" \
    --dist-init-addr "$NCCL_INIT_ADDR" \
    --nnodes 2 \
    --node-rank "$SLURM_NODEID" &

# Wait for the NCCL server to be ready on port 30000
while ! nc -z "$HEAD_NODE" 30000; do
    sleep 1
    echo "[INFO] Waiting for $HEAD_NODE:30000 to accept connections"
done

echo "[INFO] $HEAD_NODE:30000 is ready to accept connections"

# Keep the script running until the SLURM job times out
wait

Then, you can test the server by sending requests following other documents.

Thanks for aflah02 for providing the example, based on his blog post.