If all definitions look valid, Feast will sync the metadata about Feast objects to the registry. The registry is a tiny database storing most of the same information you have in the feature repository. This step is necessary because the production feature serving infrastructure won't be able to access Python files in the feature repository at run time, but it will be able to efficiently and securely read the feature definitions from the registry.

Feast CLI will create all necessary infrastructure for feature serving and materialization to work. What exactly gets created depends on which provider is configured to be used in `feature_store.yaml` in the feature repository.