Metric scraping using Prometheus
Prometheus is open source system monitoring software, which stores all metric information along with the timestamps of when they were recorded. What differentiates Prometheus from other monitoring software is its powerful multidimensional data model and a powerful query language called PromQL. It works by collecting data from various targets and then analyzing and crunching it to produce metrics. Systems can also implement HTTP endpoints that provide metrics data; these endpoints are then called by Prometheus to collect metrics data from the applications. The process of gathering metrics data from various HTTP endpoints is also called scraping.
As illustrated in the following figure, the Istio control plane and data plane components expose endpoints that emit metrics, and Prometheus is configured to scrape these endpoints to collect metrics data and store it in a time series database:
Figure 7.2 – Metric scraping...
