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ELT with Apache Airflow® and Databricks

The ELT with Apache Airflow® and Databricks GitHub repository is a free and open-source reference architecture showing how to use Apache Airflow® to copy synthetic data about a green energy initiative from an S3 bucket into a Databricks table and then run several Databricks notebooks as a Databricks job created by Airflow to analyze this data. This demo was showcased in the How to Orchestrate Databricks Jobs Using Airflow webinar.

Databricks is a popular unified data and analytics platform built around fully managed Apache Spark clusters. Using the Airflow Databricks provider package, you can create a Databricks job from Databricks notebooks running as a task group in your Airflow DAG. This lets you use Airflow's orchestration features in combination with Databricks' cheapest compute, Databricks Workflows.

For more detailed instructions on using the Airflow Databricks provider, see our Orchestrate Databricks jobs with Airflow tutorial.

DAG graph screenshot

Architecture​

Databricks reference architecture diagram.

This reference architecture consists of 3 main components:

  • Extraction: Data is moved from a local CSV file to an S3 bucket.
  • Loading: The data is loaded into a Databricks table.
  • Transformation: The data is extracted, transformed and loaded back into tables inside of Databricks by running Databricks notebooks as Databricks jobs using Airflow's DatabricksWorkflowTaskGroup and DatabricksNotebookOperator.

Airflow features​

The DAGs in this reference architecture highlight several key Airflow best practices and features:

  • Airflow Databricks provider: The Airflow Databricks provider package allows you to create Databricks jobs from Databricks notebooks running as a task group in your Airflow DAG. Additionally, it contains other operators to interact with Databricks, such as the DatabricksSqlOperator and DatabricksCopyIntoOperator shown in this demo.
  • Task groups: Task groups are a way to visually group tasks in a DAG. They can be collapsed and expanded in the Airflow UI, as well as used in dynamic task mapping to map over sets of sequential tasks.
  • Dynamic task mapping: Loading of data from the S3 bucket into the Databricks table is parallelized per file using dynamic task mapping.
  • Object Storage: Interaction with files in object storage is simplified using the experimental Airflow Object Storage API. This API allows for easy streaming of large files between object storage locations.
  • Data-driven scheduling: The second DAG in this reference architecture runs on a data-driven schedule as soon as the data it operates on is updated.

Next Steps​

If you'd like to build your own ELT/ETL pipeline with Databricks and Apache Airflow®, feel free to fork the repository and adapt it to your use case. We recommend deploying the Airflow pipelines using a free trial of Astro.

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