CloudWatch Alarms
With the metrics that CloudWatch provides, the service also allows you to monitor metrics and events that can automatically initiate actions (such as sending out an SNS notification) when certain conditions are met, in near real time. CloudWatch alarms can be used for a multitude of purposes, including detecting unusual behavior or performance issues with your AWS resources.
A metric alarm monitors a specific metric of CloudWatch. It has a threshold set for monitoring when initially created. These thresholds define the values of when the alarm will be triggered and are based on the metrics that you specify, such as CPU utilization, network traffic, or available disk space. Additionally, initial monitoring periods allow for a grace period after the alarm is created, during which nothing is triggered.
When you create a metric alarm, you select a CloudWatch metric, set a threshold value for the metric, and specify the actions to be taken when the threshold is breached...
