Three Orchestration Tools: Airflow, Kubeflow Pipelines, and MLflow Roles
Three Distinct Tool Categories
Three distinct tool categories are often conflated but serve different roles. Workflow orchestrators like Airflow, Kubeflow Pipelines, Prefect, and AWS Step Functions manage DAG execution: they schedule tasks based on dependencies and time triggers, handle retries with exponential backoff, track task state, and provide user interfaces for monitoring. Training backends like Kubernetes, AWS Batch, Apache Spark, or Ray actually execute the compute intensive work: they allocate CPUs and GPUs, run containers or processes, handle distributed communication, and report job status back to the orchestrator.
Experiment and Model Lifecycle Managers
Experiment and model lifecycle managers like MLflow or internal registries track what happened during each run: parameters like learning rate and batch size, metrics like accuracy and loss curves, artifacts like trained model files, and governance state like which model version is approved for production.
The Integration Pattern
The production pattern is integration across all three. The orchestrator parametrizes and triggers a training run on a compute backend by submitting a Kubernetes Job specification or Batch API call. The training code running on that backend logs parameters and metrics to the experiment tracker throughout execution and writes model artifacts to object storage with versioned paths. On successful completion, the orchestrator receives a success signal, validates output artifacts exist, and calls the model registry API to promote the model from candidate to production status.
Separation of Concerns Benefit
This separation of concerns means you can swap Airflow for Kubeflow Pipelines without changing your MLflow tracking code, or migrate from one cloud batch service to another without rewriting orchestration logic. Each layer evolves independently while maintaining the contract through versioned APIs and artifact references.