Models need versioning too
'I trained a new model' is not enough information. Which model? What data? Which commit produced it? How did it score? A model registry answers these.
Common registries
- Hugging Face Hub — public default; private orgs supported.
- MLflow — open-source, self-hostable.
- Weights & Biases (W&B) — full experiment tracking + registry.
- SageMaker Model Registry — AWS-native.
- Vertex AI Model Registry — GCP-native.
What metadata to record
- Source SHA (Git commit that produced the model).
- Training data version (DVC version, dataset SHA, S3 etag).
- Hyperparameters.
- Eval scores on the held-out set.
- Train environment (Docker image SHA, GPU type, library versions).
- Promotion stage (staging / production / archived).
CI integration
A successful training job uploads the model to the registry as 'staging'. A separate workflow (manual or scheduled) promotes to 'production' after eval gates pass. The serving stack pulls 'production' on startup.