Prometheus

A. Programming language used to create the tool Prometheus is

Prometheus, an open-source monitoring and alerting toolkit, is primarily implemented in the Go programming language. Go, often referred to as Golang, is known for its simplicity, efficiency, and strong support for concurrent programming, making it a suitable choice for building systems like Prometheus that require high-performance and scalability. The decision to use Go aligns with the project's goals of being easy to install, configure, and maintain while delivering robust monitoring capabilities for modern, dynamic cloud-native environments.
B. Parent company of that tool is
Prometheus is an open-source project that was originally developed at SoundCloud. However, it is now part of the Cloud Native Computing Foundation (CNCF), which is a vendor-neutral foundation that hosts and governs a variety of cloud-native projects. The CNCF is a part of the Linux Foundation and serves as the home for many popular open-source projects related to container orchestration, microservices, and cloud-native technologies. As of my last knowledge update in January 2022, Prometheus remains an active project under the CNCF umbrella. Please check the latest sources for the most up-to-date information.
C.Tool overview
Prometheus is an open-source monitoring and alerting toolkit designed to address the specific challenges posed by modern, dynamic environments, including cloud-native applications, containers, and microservices architectures. It employs a multi-dimensional data model with key-value pairs, utilizing metrics, metric names, and labels. The system adopts a pull-based model for data collection, scraping metrics endpoints from target services at regular intervals. Prometheus features a powerful query language known as PromQL, enabling users to perform sophisticated queries and aggregations on the collected metrics. With flexible alerting capabilities, users can define rules based on PromQL queries and route alerts to various channels. Service discovery mechanisms, such as DNS, Kubernetes, and Consul, facilitate automatic detection and monitoring of new services. Prometheus integrates seamlessly with visualization tools like Grafana and can be combined with other cloud-native technologies. Its horizontal scalability, local time-series database for storage, and support for remote storage solutions contribute to its popularity in monitoring and observability within dynamic and containerized environments. Additionally, Prometheus is part of the Cloud Native Computing Foundation (CNCF), emphasizing its status as an open and collaborative project within the broader ecosystem of cloud-native tools.
Purpose:
Prometheus serves a crucial purpose as an open-source monitoring and alerting toolkit tailored for the intricacies of modern, dynamic environments, such as cloud-native architectures, microservices, and containerization. Its primary objective is to enable efficient and scalable monitoring by employing a pull-based model for collecting time-series metrics data at regular intervals. With a multi-dimensional data model and a powerful query language (PromQL), Prometheus provides a flexible and expressive framework for representing and analyzing metric data. The tool supports dynamic service discovery, automatically adapting to changes in the environment. Notably, Prometheus incorporates a robust alerting system, empowering users to define rules and receive notifications for timely issue resolution. Its seamless integration with visualization tools like Grafana enhances its utility for in-depth analysis and reporting. As a part of the Cloud Native Computing Foundation (CNCF), Prometheus benefits from a collaborative community and fits into the broader ecosystem of cloud-native tools. Overall, Prometheus plays a vital role in enhancing the reliability, scalability, and observability of applications in contemporary IT landscapes.

Functionality:
Prometheus serves as a versatile and powerful monitoring and observability toolkit, offering a comprehensive array of functionalities tailored for modern computing environments. At its core, Prometheus excels in the efficient collection and storage of time-series metrics data through a pull-based model, enabling the monitoring of diverse services and applications. Its multi-dimensional data model, encompassing metric names and labels, provides flexibility in representing and categorizing metrics. The inclusion of the PromQL query language empowers users to perform sophisticated analyses and aggregations on the collected data. Noteworthy features include dynamic service discovery mechanisms that seamlessly adapt to changes in the environment, a robust alerting system for timely issue identification, and scalability to handle monitoring in large and dynamic settings. Prometheus further facilitates dynamic reconfiguration, accommodating shifts in the infrastructure. With seamless integration with visualization tools like Grafana and support for remote storage solutions, Prometheus offers a comprehensive solution for building informative dashboards and retaining metrics data. As a part of the CNCF, Prometheus benefits from an active community and fits into the broader ecosystem of cloud-native tools, enhancing its interoperability and extensibility. Overall, Prometheus stands as a vital tool for enhancing the reliability, scalability, and observability of applications in contemporary computing landscapes.

D.Logo of Prometheus

E.Open source or paid one
Prometheus is an open-source monitoring and alerting toolkit. It is freely available for use, and its source code is open to the public. Being open source means that users can view, modify, and distribute the source code according to the terms of the license, which, in the case of Prometheus, is the Apache License 2.0.

As of my last knowledge update in January 2022, Prometheus is not a commercial, paid product. Organizations and users can freely download, install, and use Prometheus without incurring licensing fees. However, it's always a good idea to check for the latest information on the official Prometheus website or related community channels for any updates or changes to the project's licensing or distribution model.