The Orchestration service can also use the Telemetry service (and its alarms) in monitoring the resource usage of stacks created using the heat stack-create command. To enable this, the Orchestration service must be installed and configured accordingly (see Section 12.2, “Overview of Telemetry Service Deployment” for more information) .

Telemetry service alarms are used by the autoscaling feature. This feature allows the Orchestration service to automatically create stacks when the usage of a specific resource reaches a certain level. To allow Orchestration to use Telemetry alarms, the following line must be uncommented in/added to the resource_registry section of /etc/heat/environment.d/default.yaml:

"AWS::CloudWatch::Alarm":  "file:///etc/heat/templates/AWS_CloudWatch_Alarm.yaml"