In machine learning (ML) projects, one of the most critical components is version management. Unlike traditional software development, managing an ML project involves not only the source code but also data and models that evolve over time. This necessitates a robust system to ensure synchronization and traceability of all these components to manage experiments, select the best models, and eventually deploy them in production. In this blog post, we will explore the best practices for managing ML models and experiments effectively.

The Three Pillars of ML Resource Management

When building machine learning models, there are three primary resources you must manage:

1. Data
2. Programs (code)
3. Models

Each of these resources is critical, and they evolve at different rates. Data changes with new samples or updates, model parameters get fine-tuned, and the underlying code could be updated with new techniques or optimizations. Managing these resources together in a synchronized fashion is essential but challenging. Therefore, you must log and track each experiment accurately.

Why You Need Model Versioning

Version management is crucial in machine learning, especially because of the following factors:

Data changes: Your training data, test data, and validation data may change or get updated.

Parameter modifications: Model hyperparameters are tweaked during training to improve performance, and the relationship between these and model performance needs to be tracked.

Model performance: Each model’s performance needs to be evaluated consistently with different datasets to ensure that the best model is selected for deployment.

Without proper version control, you may lose track of which model performed best under specific conditions, risking inefficient decision-making or, worse, deploying a sub-optimal model.

The key steps outlined to manage model versioning and experimentation in machine learning projects are as follows:

Step 1: Establishing Project and Version Names

Before embarking on your ML journey, name your project meaningfully. The project name should easily reflect the goal of the model and make sense to anyone who looks at it later. For example:

• translate_kr2en for a project focused on translating Korean to English.
• screen_clean for a project detecting scratches on mobile phone screens.

After naming your project, you need to set up a model version management system. This should track the following:

• Data used for training
• Hyperparameters
• Model architecture
• Evaluation results

These steps allow you to quickly identify which models performed best and which datasets or parameters led to success.

Step 2: Logging Experiments in a Structured Database

To manage experiments effectively, you should use a structured logging system. A database schema can help log multiple aspects of each model training iteration. For example, you can create a model management database with tables that store:

• Model name and version: Tracks different versions of a model.
• Experiments table: Records parameters, data paths, evaluation metrics, and model file paths.
• Evaluation results: Keeps track of model performance on various datasets.

Here’s an example schema for your model management database:

 ----------- ----------- ------------ ------------ ------------  
|Model Name |   Exp ID  | Parameters  | Eval Score | Model Path |
 ----------- ----------- ------------ ------------ ------------  
|translate_ |           |            |            | ./model/   |
|kr2en_v1   |   1       | lr:0.01    |Preci:0.78  | v1.pth     |
 ----------- ----------- ------------ ------------ ------------  

Every time you train a model, an entry is added to this table, allowing you to track how different parameters or data sets affected performance. This logging ensures that you never lose the context of an experiment, which is crucial for reproducibility and version management.

Step 3: Tracking Model Versions in Production

Once your model is deployed, version tracking doesn’t stop. You need to monitor how the model performs in real-world scenarios by linking inference results back to the specific version of the model that generated them. For example, when a model makes a prediction, it should log the model version in its output so that you can later assess its performance against actual data.

This allows you to trace back the model’s behavior to:

• Identify weaknesses in the current model based on production data.
• Optimize future models based on performance insights.

Maintaining a consistent version naming system enables quick identification and troubleshooting when performance issues arise.

Step 4: Creating a Model Management Service

One way to manage the versioning of models and experiments across multiple environments is by creating a model management service. This service can be built using technologies like FastAPI and PostgreSQL. The model management service would:

• Register models and their versions.
• Track experimental results.
• Provide a REST API to query or add new data to the system.

This architecture allows you to manage model versions in a structured and scalable manner. By accessing the service via API calls, engineers and data scientists can register and retrieve experimental data, making the management process more collaborative and streamlined.

Step 5: Pipeline Learning vs. Batch Learning

As you iterate on training and improving models, managing learning patterns becomes critical. There are two common learning approaches:

Pipeline Learning Pattern: Models are trained, validated, and deployed as part of an end-to-end automated pipeline. Each step is logged and versioned, ensuring transparency and reproducibility.

Batch Learning Pattern: Models are trained periodically with new data batches. Each batch should be versioned, and the corresponding models should be tagged with both model version and data batch identifiers.

Managing these learning patterns helps ensure that you can track how different training regimes or data changes impact the model’s performance over time.

Conclusion

Model version management is the backbone of any successful machine learning project. By effectively managing versions of your data, programs, and models, you can ensure that experiments are reproducible, results are traceable, and production models are easy to maintain. Adopting structured databases, RESTful services, and consistent logging will make your machine learning workflows more organized and scalable.

In the next blogs, we’ll dive deeper into managing learning patterns and comparing models for optimal performance in production environments. Stay tuned!