Introduction to alarmsAn alarm activates when a metric passes a certain threshold. If you imagine a dashboard for your metrics, alarms are like red lights that light up when conditions change, for example, when there is a problem. If you would like the platform to notify you when an alarm activates, create an Alert for it in Control view. Alerts are a group of one or more alarms. They are like a worker monitoring a group of alarms; when all the lights for the group are lit up, then the worker takes action and activates the alert. Alerts can also trigger action plans to perform automated actions when their alarms activate. After you create an alert, create an action plan in Control view with the alert as a trigger.
You can create alarms for built-in VM metrics or scaling group metrics, as well as custom metrics created using the API for VMs, scaling groups, virtual appliances, and virtual datacenters.
Display alarms in virtual datacentersTo display alarms in virtual datacenters: Go to Virtual datacenters Select a virtual datacenter or All virtual datacenters Go to Alarms
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Create an alarmBefore you begin: Configure the metrics you will use in the alarm. See VM monitoring and metrics and Custom metrics resources.
To create an alarm: | Panel |
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| Privileges: 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
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Alarm UI fields table Field | Description |
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Entity type | Select an entity with metrics from the list on the left. | Entity name | The name of the entity | Entity label | The label of the entity, which for VMs is shown in the list on the left | Entity icon | The icon that the platform displays in the UI for VMs and virtual appliances | Name | Name of the alarm with up to 128 characters. Alarm names must be unique for each metric | Description | Description of the alarm. Used together with the alarm name and VM name to identify the alarm, for example, when creating an alert | Metric | Select one of the metrics available for the VM | Metric unit | The unit of the metric. Read only | Metric description | The description of the metric. Read only | Dimension | When the metric has multiple dimensions, optionally select one or more dimensions.
For example, if a VM has multiple hard disks, then the disk read bytes metric may have a dimension for each disk | Last datapoints in period | The number of datapoints that the platform will evaluate for the metric during the elapsed time. If you request the evaluation of an alarm more frequently than
metric data is collected by the platform or sent by the provider, then the alarm will not activate. We recommend that you create alarms with longer evaluation periods, for example,
an average of 10 points over the last hour, so the transmission and collection intervals will not affect the activation of the alarm. | Statistic | Statistic that the platform will use for evaluating the alarm, which can be: average, maximum, minimum, sum, count, dev | Formula | Operator that the platform will use for evaluation of the alarm, for example, greater than.
Values can be: notequal, greaterthan, greaterthanorequalto, lessthan, lessthanorequalto, trendup, trenddown | Threshold | Value that the platform will evaluate the alarm against, if appropriate |
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. | Note |
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Troubleshooting alarms that do not triggerThe minimum value of the time period to evaluate alarms is 1 minute, but the platform collects metrics data every 2 minutes by default. The administrator can also configure the time for each hypervisor or provider. For the default configuration, to ensure that an alarm will activate, you should set the alarm to evaluate every 2 minutes as a minimum. In addition, each provider sends metrics at different intervals, for example, with Amazon Basic monitoring, data is sent every 5 minutes, and with Advanced monitoring, every minute. In contrast, for vCloud, data is available on consultation.
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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.
Edit an alarmWhen you edit an alarm, you cannot modify the metric or the entity. When you edit an alarm, there is an extra field, "Active", that shows if the alarm is activated or not. After you save the alarm, the platform will start to evaluate it again with new data when it receives the next set of metrics datapoints.
Delete an alarmYou can delete any alarm at any time, even if it is part of one or more alerts. The platform will not warn you that the alarm is used in an alert. However, you can check this in Control view. After you delete an alarm, you cannot recover it. You can also remove an alarm from an alert. | Panel |
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Privileges: Access alarms section, Manage alarms, Manage alerts |
To delete an alarm: Go to Virtual datacenters or Infrastructure → Alarms Select the alarm and delete it by clicking on the trash bin delete button
To remove an alarm from an alert: Go to Control → Alerts → edit alert Select the alarm, click the trash bin delete button, and confirm
The platform will remove it from this alert, but it will remain in all other alerts that it is associated with
If you delete a VM, the platform will delete any alarms associated with its metrics. |