This page lists all existing alerts, and shows the systems on which any are firing. To create a new alert, click the Add a new system alert link, which will bring up a page for entering its details. To remove alerts, check the boxes next to them and click the Delete Selected Alerts button.
Each alert contains one or more rules, each of which specifies a variable to monitor (like CPU load), a threshold (like 0.9), a period for which the variable must exceed the threshold, and a number of systems that this must happen on for the alert to fire.
When an alert fires, email can be sent to the Cloudmin master administrator, owners of the matching systems, or to other addresses of your choice. Each alert can also specify an interval between messages.