Before you begin:

Configure the metrics you will use in the alarm. See VM monitoring and metrics and Custom Metrics Resources.

To create an alarm:

Privilege: Access alarms section, Manage alarms

Go to Virtual datacenter → Alarms
Select virtual datacenter, virtual appliance, scaling group, or VM
Click the + add button
Enter the alarm details

For more details see GUI Create alarm
Click Save

The platform will create the alarm for the metric. If you would like the platform to notify you when an alarm is triggered, create an Alert.

Troubleshooting alarms that do not trigger

Although the minimum value of the time period for alarm evaluation is 1 minute, the platform collects metrics data every 2 minutes by default but it can also be configured for each hypervisor or provider.
For the default configuration, to ensure that an alarm will activate, it should be evaluated at intervals of greater than 2 minutes.
In addition, each provider transmits metrics at different intervals, for example, with Amazon Basic monitoring, data is sent every 5 minutes, and with Advanced monitoring, every minute, whereas for vCloud, data is available on consultation.

For a scaling group, an alarm on a metric of the VM in the base workload will receive input from the metrics of all VMs in the scaling group. This means the base workload and/or the clone VMs. So an alarm for a scaling group can activate, even if the base workload is not deployed.

For API documentation about alarms on an entity, see the API documentation for the entity's resource. For example, for VMs, see VirtualMachinesResource.