title: Airflow DAG "seems to be existing only locally. The master scheduler doesn't seem to be aware of its existence"
body: <p>I used airflow for workflow of Spark jobs. After installation, I copy the DAG files into DAGs folder set in airflow.cfg. I can backfill the DAG to run the BashOperators successfully. But there is always a warning like the one mentioned. I didn't verify if the scheduling is fine, but I doubt scheduling can work as the warning said the master scheduler doesn't know of my DAG's existence. How can I eliminate this warning and get scheduling work? Anybody run into the same issue who can help me out?</p>