Fine-Tuning Qwen3 with LoRA Using NVIDIA NeMo AutoModel: A Complete Single-GPU Google Colab Workflow Tutorial

NVIDIA NeMo AutoModel: A Complete Single-GPU Google Colab Workflow Tutorial">

In this tutorial, we build an end-to-end NVIDIA NeMo AutoModel workflow in Google Colab and use a single GPU to explore the same configuration-driven training architecture that scales to distributed multi-GPU environments. We verify the available CUDA hardware and precision support, install NeMo AutoModel directly from its source repository, load an official Qwen3-0.6B LoRA fine-tuning recipe, and programmatically adapt its precision, batch-size, checkpointing, and scheduler settings for a constrained Colab runtime. We then launch parameter-efficient fine-tuning through the automodel command-line interface, locate and reload the generated LoRA checkpoint, and compare outputs from the original and fine-tuned models. Finally, we use NeMoAutoModelForCausalLM through the Python API to demonstrate how NeMo AutoModel integrates NVIDIA-optimized execution paths while preserving the familiar Hugging Face model interface.

We import the core Python libraries required for file handling, process execution, path management, and formatted output. We define the repository, working, and checkpoint directories used throughout the workflow. We also create a reusable shell-command function that streams command output and raises errors when execution fails.

We verify that the Colab runtime provides a CUDA-enabled GPU and inspect its name, memory capacity, and bfloat16 support. We clone the NVIDIA NeMo AutoModel repository when it is not already available and install the package directly from source. We then install the supporting YAML and PEFT libraries and confirm that the NeMo AutoModel package imports correctly.

We locate an official PEFT recipe, load its YAML configuration, and inspect the original training settings. We recursively adapt the precision and batch size parameters to fit the recipe on a single Colab GPU while preserving its original structure. We also limit the training duration, configure checkpoint output, save the patched recipe, and extract the Hugging Face model identifier.

We launch Qwen3-0.6B LoRA fine-tuning on the HellaSwag dataset through the NeMo AutoModel command-line interface. We turn off unnecessary Hugging Face transfer and tokenizer parallelism features to keep the Colab run more predictable. We also include a fallback command that supports older NeMo AutoModel CLI syntax when the primary invocation fails.

We load the tokenizer and base causal language model, generate a deterministic response, and establish a baseline for comparison. We search the training output directories for the latest LoRA checkpoint or adapter files created during fine-tuning. We then attach the adapter with PEFT, generate the fine-tuned response, and release GPU memory after evaluation.