Lambda functions written in Python to perform AWS Aurora databases vertical autoscaling:

1. Alarm (rds_vscale_alarm_lambda.py) is a lambda function triggered when the CPU Load Average value exceeds a threshold. It finds a suitable small instance within an RDS cluster and performs its scaling to the next possible instance type.
2. Event (rds_vscale_event_lambda.py) is a lambda function triggered when the instance modification initiated by Alarm is completed. It scales the rest smallest RDS instances bringing them to the same size.

This code is used (and better described) in the following article:

• “Implementing vertical autoscaling for Aurora databases using Lambda functions in AWS” (published in April 2024)