Prometheus is an open-source systems monitoring and alerting toolkit that was originally built at SoundCloud. It is a versatile monitoring tool that can be used to monitor a variety of infrastructure and application metrics. Prometheus collects and stores its metrics as time series data, i.e. metrics information is stored with the timestamp at which it was recorded, alongside optional key-value pairs called labels. Some common use cases of Prometheus include:

• Monitoring numeric metrics from services that run 24/7 and allow metric data to be accessed via HTTP endpoints.
• Monitoring Kubernetes workloads, as Prometheus was built for a cloud-native environment and has become one of the most popular monitoring tools for cloud-native environments.
• Monitoring the operating system, such as hard disk space, CPU usage, memory usage, website uptime, and the number of HTTP requests for each page.

Prometheus can display collected data in tabular or graph form, shown in its web-based user interface. It can also be used with APIs to integrate with third-party visualization solutions like Grafana. Prometheus is designed for reliability, to be the system you go to during an outage to allow you to quickly diagnose problems. Each Prometheus server is standalone, not depending on network storage or other remote services. You can rely on it when other parts of your infrastructure are broken, and you do not need to set up extensive infrastructure to use it.