Alerts

[User Guide](User Guide)

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#Working with Alerts Argus evaluates alerts on metric data and notifies users when trigger thresholds are exceeded. Alerts are scheduled and executed per the CRON entry specified when the alert was created. An alert is associated with at least one trigger and one notification. You can associate a trigger with more than one notification, and a notification with more than one trigger.

You can access the Alert interface via the link at the top of the Argus interface.

##Alert Structure
An alert includes the CRON entry, enabled, expression, Id, missing data notification, name, and owner.

Component	Description
CRON entry	Time and frequency of the alert
Enabled	Enabled for evaluation
Expression	Metric expression to evaluate trigger conditions
ID	ID of the alert
Missing data notification	Notify owner if metric expression doesn't contain data
Name	Alert name
Owner	Owner of the alert

##Create an Alert

1. On the Argus home page, click the Alerts tab.
2. Click the Add button.
   The alert is created with default data under Alert List.
3. To change the default values, click the alert name.

The Argus scheduler uses CRON Entry to schedule the alert. The CRON Entry represents the time and frequency of alert evaluation.

Expression is used to retrieve the metric data to evaluate the triggering conditions.

##Trigger Structure
A trigger includes the ID, inertia millis, name, primary threshold, secondary threshold, and type.

Component	Description
ID	ID of the trigger
Inertia millis	Number of milliseconds for which the conditions must be met before the trigger is fired
Name	Trigger name
Primary threshold	Operand for the comparison
Secondary threshold	Operand for the BETWEEN and NOT_BETWEEN operators
Type	Trigger comparison operator

##Create a Trigger A trigger defines a threshold value. The trigger types are less than, greater than, and equal to the time period. When the trigger condition is met, a notification is sent. You can associate a trigger with more than one notification.

1. Click Triggers and then click the Add button.
2. A Trigger is created by selecting the Triggers tab then clicking the add button.
   The trigger is created with default data.
3. To change the default values,

Inertia Mills is a time period in milliseconds for which the trigger condition is meant to send a notification.

##Notification Structure
A notification includes the cooldown millis, ID, metrics to annotate, name, subscription, and cooldown millis.

Component	Description
Cooldown millis	Number of milliseconds the notification is on cooldown after a notification is sent
ID	ID of the notification
Metrics to annotate	Metric identifiers
Name	Notification name
Subscriptions	Subscribers of the alert
Type	Notification type

##Create a Notification A notification defines how you are notified when a trigger fires. You can associate a notification with more than one trigger.

1. Click the Notifications tab.
2. Click the Add button. The notification is created with default data.
3. Click the Triggers button to display all triggers.
4. Select the triggers to associate with the notification by selecting their’ IDs.

Metrics to Annotate is a comma-separated list of metric expressions. When a notification is sent, an annotation is created. You can retrieve annotations via a REST endpoint or view them on a dashboard.

Cooldown Mills defines the time period in milliseconds when the notification is not sent. No further notifications are sent for the notification until it comes off of cooldown. The cooldown expiration is a read only field.

Argus supports the following notifiers:

• Audit notifier writes the notification to the Argus database. Subscription fields are left blank.
• Email notifier sends an email to subscribers whose email addresses are mentioned in the Subscriptions field. The subscription field contains a comma-separated list of email addresses.