What is Prometheus? Definition from WhatIs.com.

Prometheus is an open source monitoring and alerting toolkit for microservices and containers that provides flexible queries and real time notifications. Prometheus assists in IT monitoring and makes the department aware of any issues with their application program interfaces (APIs) or other connected applications and services. The software checks for irregular traffic that could be a sign of an attack or compromise. Prometheus metrics can be used to track statistics such as top selling products, top reviewed products and order to ship times.

How Prometheus works

Prometheus can be run within Docker or Go applications. The monitoring software is a time series database with a user interface (UI) and sophisticated, flexible querying language called PromQL.

Prometheus gathers metrics from instrumented jobs either directly or through an intermediary gateway designed for temporary jobs. The samples are stored locally and scanned by rules in order to either collect and record a new time series from the existing information or create alerts. These metrics are then displayed by way of counters, gauges and histograms. Data is transmitted by HTTP using plaintext or by more efficient protocols.

Features of Prometheus include:

• various modes of graphing and Dashboard support;
• the occurrence of time series collection through a pull model over HTTP;
• a multidimensional data model featuring time series data that is identified with a metric name or with key-value pairs (KVP);
• the ability to use PromQL to support the multidimensionality of the data model;
• autonomous single server nodes and zero reliance on distributed storage;
• discovery of the target through static configuration or service discovery; and
• the ability to push time series through an intermediary gateway.

Components of Prometheus are mostly written in the Go programming language and can be feasibly built and deployed as static binaries. Many components are optional.

The components of the Prometheus system include:

• the primary Prometheus server that is responsible for scraping and storing time series data;
• an alert manager that controls alerts;
• a push gateway for temporary, or short-lived, jobs;
• client libraries that apply application code;
• exporters with special purposes specifically for dealing with services like HAProxy, Graphite and StatsD; and
• a collection of support tools.

Uses of Prometheus

IT departments use Prometheus to try to catch intrusions and issues in cloud environments as soon as possible. It is also used to present site, service and application data and product information that is relevant to site visitors. The tool has been used by companies such as Boxever, Docker, Google, Red Hat, Weaveworks, CoreOs, Ericsson and DigitalOcean.

Prometheus helps those running cloud managed services, applications and sites to ensure proper function for customers. Aside from the behind the scenes work, Prometheus is important for customer-facing functions as well. The software displays relevant data to customers about products, sales, reviews and trends.

Benefits of Prometheus

Prometheus was designed to quickly diagnose problems. It can operate with both machine-centric monitoring and monitoring of highly complex service-oriented architectures. Its strong use in multidimensional data collection and querying is especially beneficial.

Since the Prometheus server is independent, it does not need to rely on remote service like network storage. This means it can still be used when other parts of the infrastructure are malfunctioning or broken. Furthermore, construction of a complex, large infrastructure is unnecessary for its operation.  

History of Prometheus

Prometheus is named after the Greek legend of Prometheus, a titan who defied the gods and gave fire to humanity. For this action, Prometheus was chained to a boulder where an eagle, the earthen symbol of Zeus, would eat the other immortal’s liver, every day, for eternity.

Since its introduction in 2012, Prometheus has been adopted by a multitude of companies and organizations. However, it remains independent with the management and maintenance of the project occurring separate of any company.

In 2016, Prometheus joined the Cloud Native Computing Foundation (CNCF). It is the second project hosted by the foundation; the first project was Kubernetes.