I'd like to get a notification when my server's free disk space drops below 10GB. How do I configure cfengine3 to tell me when / has less than 10GB of free space?
This question looks a lot like that question
To receive an email with cfengine 3, you need to use the cf-execd rather than the cf-agent, and define somewhere where to send the email :
Reference : cfengine documentation
So the daemon will send any new output from the agent to the email adress you specified.
Hope this will help