Monitoring should be setup for all of the Cerberus services with the tools used by your organization.
A Health Check Lambda / API Gateway endpoint that provides an end-to-end test of the general health of the production Cerberus environment. It checks that a lambda can authenticate with Cerberus which will exercise the Cerberus Management Service (CMS) and its RDS DB. The lambda can be invoked via the AWS API Gateway and monitored by another tool.
Monitoring HTTP response codes CMS gives a good indication of health and activity within the system, e.g. aggregating data from /var/log/cms/cms.log and displaying on a dashboard or metric based alerting.