With an email alert is there anyway to show the amount of used space on a device? I tried using {{http://system.disk.in|system.disk.in_use}} in the email template but when i send the test email it does not show any number. This is for a linux AWS instance.
In metric based query monitors, you’ll want to use the variable {{value}}
which will provide the value of the metric that breached the alert threshold.
You can find this, and other useful variables for alerting documented here: https://docs.datadoghq.com/monitors/notifications/?tab=is_alert#variables