Alarms
Table of Contents
1. Alarms
The most common kind of alarm is a metric alarm which is an alarm linked to a Cloudwatch metric (though more sophisticated alarms are available). Alarms of this kind are typically configured to trigger after said metric exceeds a threshold in a given number of time periods.
Actions are associated with alarms and are dispatched once alarms reach ALARM state, a common example would be to send a notification to an SNS topic.
1.1. Example:
If you alarm on 4 out of 5 data points with a period of 1 minute, then:
datapointsToAlarm= 4evaluationPeriods= 5period= 1 minute
threshold is what determines whether a data point (calculated from the metric definition) is "bad" and contributes to the 4 out of 5 data points rule.
See also: https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_concepts.html