AWS Budgets now allows you to set RI utilization alerts for your Amazon Redshift, Amazon RDS, and Amazon ElastiCache reservations, in addition to setting alerts on your Amazon EC2 Reserved Instances.
RI Utilization alerts allow you to set a custom utilization target for one or more reservations pertaining to the same AWS service, and notify you when your reservation utilization drops below that threshold. Reservation utilization tracks the percentage of reserved hours that were used by matching instances, and can be monitored by AWS Budgets at a daily, monthly, quarterly, or yearly level. You can monitor your reservation utilization at an aggregate level (e.g., monthly utilization of your Amazon RDS fleet) or at a granular level of detail (e.g., daily utilization of db.m4.2xlarge instances running in a specific region). From there, you can define up to five notifications. Each notification can be sent to a maximum of ten email subscribers, and can be broadcast to an Amazon Simple Notification Service (Amazon SNS) topic.