I am not sure what mapping in YAMl file means, can someone advise what does mapping in YAML file means?
YAML is a very simple, text/human-readable annotation format that can be used to store data. YAML keeps data stored as a map containing keys and values associated to those keys. This map is in no particular order, so you can reorder it at will. Each pair is in the format KEY: VALUE When the value is a text string enclose the value with quotes. Some examples below:
KEY1: 'HELLO' HOST_NUMBER: 1