updating airflow instructions

docs/_source/iaas_setup.rst

@@ -589,6 +589,12 @@ airflow db migrate
 edit the resulting ${AIRFLOW_HOME}/airflow.cfg file on line 435 to the mysyl database
 sql_alchemy_conn = mysql+mysqldb://airflow_user:<password_from_above>@localhost:3306/airflow_db
 
+while you are editing the config file, set the timezone to be your local timezone, rather than UTC. As this system works
+on a regular, local timezone, daylight saving hours need to be taken into account so it runs at the same local time each day.
+
+default_timezone = Europe/London
+(note that the UI has a dropdown in the top right to set the displayed timezone, but the scheduler will run on the server timezone)
+
 **install the mysql provider**
 
 sudo apt install gcc;
@@ -617,6 +623,8 @@ airflow users  create --role Admin --username admin --email lb584@cam.ac.uk --fi
 
 (you can set the password to something more secure when logged in)
 
+
+
 run the scheduler and the webserver
 
 airflow scheduler;