The defaults.yml file is where the environments that you are running in antfarm are defined. This file usually resides in .antfarm/config
The default environment with no other definitions nor the use of the -e option is 'antfarm'. The defaults.yml file initially has the following:
environment: antfarm log_level: warn
If other environments are added (userenvironment1 & userenvironment2 are examples here), the defaults.yml file look like:
environment: antfarm log_level: warn userenvironment1: adapter: postgresql userenvironment2: adapter: postgresql . . .
and so on