Cloud Monitoring
What is it
Cloud Monitoring is a fully managed product for service and system monitoring and alerting.
When to use it
Use Cloud Monitoring to gain observability into your backend services and systems, and to create alerting policies to automatically detect and alert on errors in production.
Use the integration with PagerDuty to ensure that alerts are sent to the appropriate on-call rotation.
If you have used the Cloud Runner SDK, your service or system should already have integration with Cloud Monitoring configured.
How to learn it
Read the documentation.
Especially read the alerting UI documentation to learn how to create alerts on monitoring metrics.
Definitely make sure to have understood how to work with Cloud Monitoring before going on-call, as it will be part of your bread and butter tools for diagnosing and resolving issues in production.