MLFlow Client Integration

Introduced in GitLab 15.6 as an Alpha release with a flag named ml_experiment_tracking. Disabled by default.

MLFlow Client Integration is an experimental feature being developed by the Incubation Engineering Department, and will receive significant changes over time.

MLFlow is one of the most popular open source tools for Machine Learning Experiment Tracking. GitLabs works as a backend to the MLFlow Client, logging experiments. Setting up your integrations requires minimal changes to existing code.

GitLab plays the role of proxy server, both for artifact storage and tracking data. It reflects the MLFlow Scenario 5.

Enable MLFlow Client Integration

Complete this task to enable MLFlow Client Integration.


  • A personal access token for the project, with minimum access level of api.
  • The project ID. To find the project ID, on the top bar, select Main menu > Projects and find your project. On the left sidebar, select Settings > General.
  1. Set the tracking URI and token environment variables on the host that runs the code (your local environment, CI pipeline, or remote host).

    For example:

    export MLFLOW_TRACKING_URI="http://<your gitlab endpoint>/api/v4/projects/<your project id>/ml/mlflow"
    export MLFLOW_TRACKING_TOKEN="<your_access_token>"
  2. If your training code contains the call to mlflow.set_tracking_uri(), remove it.

When running the training code, MLFlow will create experiments, runs, log parameters, metrics, and artifacts on GitLab.

After experiments are logged, they are listed under /<your project>/-/ml/experiments. Runs are registered as Model Candidates, that can be explored by selecting an experiment.


  • The API GitLab supports is the one defined at MLFlow version 1.28.0.
  • API endpoints not listed above are not supported.
  • During creation of experiments and runs, tags are ExperimentTags and RunTags are stored, even though they are not displayed.
  • MLFlow Model Registry is not supported.

Supported methods and caveats

This is a list of methods we support from the MLFlow client. Other methods might be supported but were not tested. More information can be found in the MLFlow Documentation.


Accepts both experiment_name and experiment_id


  • Nested runs have not been tested.
  • run_name is not supported

log_param(), log_params(), log_metric(), log_metrics()

Work as defined by the documentation

log_artifact(), log_artifacts()

artifact_path must be empty string.


This is an experimental method in MLFlow, and partial support is offered. It stores the model artifacts, but does not log the model information. The artifact_path parameter must be set to '', because Generic Packages do not support folder structure.