only airflow container
airflow container has the following mandatory services:
- postgres (optional?)
- redis : broker that forwards messages from scheduler to worker
- webserver : webserver available at http://localhost:8080
- scheduler : monitors all tasks and DAGs, then triggers the task instances once their dependencies are complete
- worker : worker that executes the tasks given by the scheduler
- flower : for monitoring the environment
- airflow-init : initialization service
descriptions provided by official doc
in x-airflow-common, the volumes are mapped from inside to outside. on the local machine (a folder named /dags on current directory is created to bridge the inside of docker at /opt/airflow/dags)
connectors automatically bring and sink data from airflow