By default, Airflow disables new DAGs. This can be overridden when constructing the DAG. The Admin UI shows us which DAGs are paused and we can toggle DAGs on or off. Enable all 3 DAGs to see how the scheduler responds.
After a few seconds we refresh the page and we may see something like the following:
Note that DAG Runs have already been scheduled and run. This is controlled by the scheduler which considers the start and end dates of our DAGs and the scheduling interval we set in our DAG definitions.
Recall the default args and for example_dag definition from the DAG factory YAML file section:
All 3 DAGs were scheduled to run between 2018-03-01 and 2018-03-05 by default.
And above we see the schedule interval for example_dag which was overridden from the defaults.
You can wait for any DAG run to finish or click on a DAG that is running to bring up the history of runs for that DAG:
This brings up the DAG Run history for the given DAG. We can also see all DAG run histories by utilizing the Browse > DAG Runs drop down (shown below):