# Basic Airflow architecture

Primarily intended for development use, the basic [[Airflow]] architecture with the Local and Sequential executors in an excellent starting point for understanding the architecture of Apache Airflow

{{ https://airflow.apache.org/docs/apache-airflow/stable/_images/arch-diag-basic.png }}

There are a few components to note:

  - [[Metadata Database]]: Airflow uses a [[SQL]] database to store metadata about the data pipelines being ru. In the diagram above, this is represented as [[Postgres]] which is extremely popular with Airflow. Alternate database supported with Airflow include [[MySQL]].
  - [[Web Server]] and [[Scheduler]]: The Airflow web server and Scheduler are separate processes run (in this case) on the local machine and interact with the database mentioned above.
  - The [[Executor]] is shown separately above, since it is commonly discussed within Airflow and in the documentation, but in reality it is NOT a separate process, but run within the Scheduler.
  - The [[Worker(s)]] are separate processes which also interact with the other components of the Airflow architecture and the metadata repository.
  - [[airflow.cfg]] is the Airflow configuration file which is accessed by the Web Server, Scheduler, and Workers.
  - [[DAGs]] refers to the [[DAG]] files containing [[Python]] code, representing the data pipelines to be run by [[Airflow]]. The location of these files is specified in the Airflow configuration file, but they need to be accessible by the Web Server, Scheduler, and Workers.



## Ref

- https://airflow.apache.org/docs/apache-airflow/stable/start.html