# Guide de permutation à chaud LoRA

### :shaved\_ice: vLLM LoRA Hot Swapping / LoRA dynamiques

Pour activer le service LoRA pour au plus 4 LoRA à la fois (qui sont échangés à chaud / modifiés), définissez d'abord le drapeau d'environnement pour autoriser l'échange à chaud :

```bash
export VLLM_ALLOW_RUNTIME_LORA_UPDATING=True
```

Ensuite, servez-le avec la prise en charge de LoRA :

```bash
export VLLM_ALLOW_RUNTIME_LORA_UPDATING=True
vllm serve unsloth/Llama-3.1-8B-Instruct \
    --quantization fp8 \
    --kv-cache-dtype fp8
    --gpu-memory-utilization 0.8 \
    --max-model-len 65536 \
    --enable-lora \
    --max-loras 4 \
    --max-lora-rank 64
```

Pour charger un LoRA dynamiquement (définissez également le nom du lora), faites :

```bash
curl -X POST http://localhost:8000/v1/load_lora_adapter \
    -H "Content-Type: application/json" \
    -d '{
        "lora_name": "LORA_NAME",
        "lora_path": "/path/to/LORA"
    }'
```

Pour le retirer du pool :

```bash
curl -X POST http://localhost:8000/v1/unload_lora_adapter \
    -H "Content-Type: application/json" \
    -d '{
        "lora_name": "LORA_NAME"
    }'
```

Par exemple lors du fine-tuning avec Unsloth :

{% code overflow="wrap" %}

```python
from unsloth import FastLanguageModel
import torch
model, tokenizer = FastLanguageModel.from_pretrained(
    model_name = "unsloth/Llama-3.1-8B-Instruct",
    max_seq_length = 2048,
    load_in_4bit = True,
)
model = FastLanguageModel.get_peft_model(model)
```

{% endcode %}

Puis après l'entraînement, nous sauvegardons les LoRA :

```python
model.save_pretrained("finetuned_lora")
tokenizer.save_pretrained("finetuned_lora")
```

Nous pouvons ensuite charger le LoRA :

{% code overflow="wrap" %}

```bash
curl -X POST http://localhost:8000/v1/load_lora_adapter \
    -H "Content-Type: application/json" \
    -d '{
        "lora_name": "LORA_NAME_finetuned_lora",
        "lora_path": "finetuned_lora"
    }'
```

{% endcode %}


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