How do I get rid of CloudWatch metrics that I no longer need?
What was in trouble
CloudWatch metrics that are no longer needed continue to remain on the management console.
Under what conditions will the target metric be deleted?
What should I do?
Manual deletion of metrics is not currently supported, but if new data for the target metric is not published, it will automatically expire and be deleted after 15 months.
Delete Unused CloudWatch Alarms
Amazon CloudWatch alarms are a powerful tool used to receive alerts when CloudWatch metrics meet or pass certain thresholds. For example, you can create a CloudWatch alarm that will trigger when an RDS instance’s available storage falls below 10%.
Sometimes, when AWS resources are deleted, old CloudWatch alarms may remain around. This causes two problems:
A stale CloudWatch alarm will sit idle in the “Insufficient Data” list, and
It will continue to cost you $0.10 per alarm per month (or more, regarding to your location)
Delete Unused CloudWatch Alarms Action
You can delete CloudWatch alarms which are sitting in your AWS account, but have no metrics or metric data to trigger the alarm.
The action looks for any Cloudwatch alarms which are in an “INSUFFICIENT_DATA” state, and optionally, possess a matching namespace (such as AWS/EC2). Compatible alarms are checked for compatible metrics or metric data, and if none are found, then, the alarm is deleted.
If your AWS account contains many alarms sitting in the “INSUFFICIENT_DATA” state, then this action can help to lower your AWS costs.