Fine-tuning LLMs for text generation

This section covers how to fine-tune a language model for text generation and consume it in LocalAI.

Requirements link

For this example you will need at least a 12GB VRAM of GPU and a Linux box.

Fine-tuning link

Fine-tuning a language model is a process that requires a lot of computational power and time.

Currently LocalAI doesn’t support the fine-tuning endpoint as LocalAI but there are are plans to support that. For the time being a guide is proposed here to give a simple starting point on how to fine-tune a model and use it with LocalAI (but also with llama.cpp).

There is an e2e example of fine-tuning a LLM model to use with LocalAI written by @mudler available here.

The steps involved are:

• Preparing a dataset
• Prepare the environment and install dependencies
• Fine-tune the model
• Merge the Lora base with the model
• Convert the model to gguf
• Use the model with LocalAI

Dataset preparation link

We are going to need a dataset or a set of datasets.

Axolotl supports a variety of formats, in the notebook and in this example we are aiming for a very simple dataset and build that manually, so we are going to use the completion format which requires the full text to be used for fine-tuning.

A dataset for an instructor model (like Alpaca) can look like the following:

  [
 {
    "text": "As an AI language model you are trained to reply to an instruction. Try to be as much polite as possible\n\n## Instruction\n\nWrite a poem about a tree.\n\n## Response\n\nTrees are beautiful, ...",
 },
 {
    "text": "As an AI language model you are trained to reply to an instruction. Try to be as much polite as possible\n\n## Instruction\n\nWrite a poem about a tree.\n\n## Response\n\nTrees are beautiful, ...",
 }
]
  

Every block in the text is the whole text that is used to fine-tune. For example, for an instructor model it follows the following format (more or less):

  <System prompt>

## Instruction

<Question, instruction>

## Response

<Expected response from the LLM>
  

The instruction format works such as when we are going to inference with the model, we are going to feed it only the first part up to the ## Instruction block, and the model is going to complete the text with the ## Response block.

Prepare a dataset, and upload it to your Google Drive in case you are using the Google colab. Otherwise place it next the axolotl.yaml file as dataset.json.

Install dependencies link

  # Install axolotl and dependencies
git clone https://github.com/OpenAccess-AI-Collective/axolotl && pushd axolotl && git checkout 797f3dd1de8fd8c0eafbd1c9fdb172abd9ff840a && popd #0.3.0
pip install packaging
pushd axolotl && pip install -e '.[flash-attn,deepspeed]' && popd

# https://github.com/oobabooga/text-generation-webui/issues/4238
pip install https://github.com/Dao-AILab/flash-attention/releases/download/v2.3.0/flash_attn-2.3.0+cu117torch2.0cxx11abiFALSE-cp310-cp310-linux_x86_64.whl
  

Configure accelerate:

  accelerate config default
  

Fine-tuning link

We will need to configure axolotl. In this example is provided a file to use axolotl.yaml that uses openllama-3b for fine-tuning. Copy the axolotl.yaml file and edit it to your needs. The dataset needs to be next to it as dataset.json. You can find the axolotl.yaml file here.

If you have a big dataset, you can pre-tokenize it to speedup the fine-tuning process:

  # Optional pre-tokenize (run only if big dataset)
python -m axolotl.cli.preprocess axolotl.yaml
  

Now we are ready to start the fine-tuning process:

  # Fine-tune
accelerate launch -m axolotl.cli.train axolotl.yaml
  

After we have finished the fine-tuning, we merge the Lora base with the model:

  # Merge lora
python3 -m axolotl.cli.merge_lora axolotl.yaml --lora_model_dir="./qlora-out" --load_in_8bit=False --load_in_4bit=False
  

And we convert it to the gguf format that LocalAI can consume:

  
# Convert to gguf
git clone https://github.com/ggerganov/llama.cpp.git
pushd llama.cpp && make LLAMA_CUBLAS=1 && popd

# We need to convert the pytorch model into ggml for quantization
# It crates 'ggml-model-f16.bin' in the 'merged' directory.
pushd llama.cpp && python convert.py --outtype f16 \
    ../qlora-out/merged/pytorch_model-00001-of-00002.bin && popd

# Start off by making a basic q4_0 4-bit quantization.
# It's important to have 'ggml' in the name of the quant for some
# software to recognize it's file format.
pushd llama.cpp &&  ./quantize ../qlora-out/merged/ggml-model-f16.gguf \
    ../custom-model-q4_0.bin q4_0
  

Now you should have ended up with a custom-model-q4_0.bin file that you can copy in the LocalAI models directory and use it with LocalAI.