Prometheus is a solution that contantly keeps track of the key health and performance metrics of an application and infrastructure. It collects metrics from your application and stores them in a time-series database, enabling you to analyze trends and patterns over time. For example, you can use Prometheus to track the CPU utilization of your application and set up alerts to notify you if it exceeds a certain threshold.
One of the key features of Prometheus is its powerful query language (PromQL), which enables you to extract insights from your metrics. For instance, you can use PromQL to calculate the 90th percentile of response times across your web servers, helping you identify servers that could be underperforming.
However, monitoring is proving to be insufficient for modern applications, as it doesn't highlight why or how issues occur. Developers are increasingly adopting distributed tracing to plug the gaps from monitoring.