A real-world use case
Prometheus (https://github.com/prometheus/prometheus) is a tool that is used for monitoring applications and clusters by collecting metrics exported by those applications and storing them in a time series manner. In Chapter 5, Developing an Operator – Advanced Functionality, we implemented basic Prometheus metrics in the nginx Operator to expose aggregate information about the total reconciliation attempts made by the Operator. This was just one small example of the potential application architecture designs that rely on Prometheus for monitoring.
Prometheus overview
Along with scraping and aggregating metrics, Prometheus also defines a data model for creating different types of metrics and implementing them in applications. This model is instrumented via the clients provided by Prometheus in various languages, including Ruby, Python, Java, and Go. These clients make it easy for application developers to export metrics in a format that is compatible...