Comment 1 for bug 1498556

So at least from the keystoneauth perspective this is what we do. With the addition that to handle the default domain case we have the OS_DEFAULT_DOMAIN_ID/NAME environment variables/flags. This would let people do OS_DEFAULT_DOMAIN_ID=default and have this value used for OS_USER_DOMAIN_ID/NAME and OS_PROJECT_DOMAIN_ID/NAME when one is not set.

Whilst i understand the desire to just set the default domain id to default and leave it, i think the OS_DEFAULT_DOMAIN_ID works well because if you are in another domain you can set DEFAULT_DOMAIN_NAME=pepsi.com and never think about it again.