Alarms

Alarms are used to generate alerts when a metric falls outside of a defined threshold.

States

There is only a single alarm level:

• OK indicates that the alarm is not in violation of the configured threshold.
• ALARM indicates that the alarm has breached the configured threshold.
• INSUFFICIENT indicates that an insufficient number of samples have been taken to evaluate the alarm.

More complex configurations with multiple alarm levels (e.g. warning, critical) must be created as separate alarms.

Actions

An alarm can raise actions on state changes between OK and ALARM. Actions might include:

• Simple Notification Service notification
• Email
• Auto Scaling
• EC2 action (terminate, reboot)

They can be used to trigger scaling operations via SNS.

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Backlinks

• PagerDuty (public)
• Application Auto Scaling (public)