What Is CentOS?

CentOS, an acronym for Community Enterprise Operating System, is a Linux distribution that aims to provide a free and open-source alternative to Red Hat Enterprise Linux (RHEL). It is built from the same source code as RHEL, but with the branding and trademarked elements removed. CentOS is developed and maintained by a community of volunteers, making it a community-driven project.

CentOS Stream vs. CentOS Linux

Both are open source Linux distros, versions of CentOS, and part of the overall enterprise Linux ecosystem. CentOS Stream serves as the open source development platform for upcoming releases of Red Hat Enterprise Linux. CentOS Stream is what will become Red Hat Enterprise Linux, while CentOS Linux is derived from source code released by Red Hat. Historically, each version of CentOS Linux reflected major versions of Red Hat Enterprise Linux—both used the RPM package manager system and maintained similar functionality, compatibility, and bug fixes.

CentOS Stream tracks just ahead of Red Hat Enterprise Linux releases and is continuously delivered as the source code that will become minor releases of Red Hat Enterprise Linux. CentOS Stream makes Red Hat Enterprise Linux developmental source code available so that community members have a place to contribute and test code in tandem with Red Hat Enterprise Linux engineers. Its community members—along with Red Hat partners and ecosystem developers—can download, adapt, submit patches, and suggest changes that could be included in the next minor release of Red Hat Enterprise Linux.

CentOS Linux is downstream of Red Hat Enterprise Linux—most often used for development and deployment—and doesn’t have a contribution model. Updates to CentOS Linux will discontinue between 2021 and 2024.

Including the Fedora project, the open source development cycle of Red Hat Enterprise Linux is:

1. Fedora: The upstream project on which future Red Hat Enterprise Linux major releases are based.
2. CentOS Stream: A preview of upcoming Red Hat Enterprise Linux minor versions.
3. Red Hat Enterprise Linux: The official, hardened, and fully supported enterprise operating system product.
4. CentOS Linux: A community-supported and -produced Linux distro derived from source code released by Red Hat, scheduled to be discontinued between 2021-2024.
   

   Here are some key details about CentOS explained in more detail:

   1. Relationship to Red Hat Enterprise Linux (RHEL): CentOS is closely related to RHEL, as it is essentially a clone of the RHEL distribution. CentOS is built from the same source code that Red Hat releases for RHEL, ensuring high compatibility between the two distributions. This means that CentOS users can leverage the extensive software ecosystem built for RHEL, including third-party applications and software packages.
   2. Stability and Long-Term Support: CentOS is renowned for its stability, reliability, and long-term support. It is designed to be a robust operating system suitable for mission-critical server deployments. CentOS follows a predictable release cycle, offering long-term support versions that receive updates and security patches for an extended period. This stability makes CentOS a popular choice for enterprises and organizations that require a reliable and secure operating system.
   3. Free and Open Source: CentOS is released under an open-source license, which means it can be freely used, modified, and distributed. It provides a cost-effective alternative to RHEL, as it does not require the purchase of commercial licenses or subscriptions. The CentOS community ensures that the distribution remains free, adhering to the principles of open-source software.
   4. Binary Compatibility: CentOS strives to be binary compatible with RHEL. This means that software packages built for RHEL can be installed and run on CentOS without any modifications or compatibility issues. The compatibility extends to both the operating system itself and the available software repositories, providing users with a wide range of software options.
   5. Package Management: CentOS uses the YUM (Yellowdog Updater, Modified) package management system, which is also used in RHEL. YUM allows users to easily install, update, and manage software packages. The CentOS repositories provide a vast selection of pre-built packages, including applications, libraries, development tools, and system utilities.
   6. Server and Enterprise Focus: CentOS is widely used in server and enterprise environments. Its stability, reliability, and compatibility with RHEL make it suitable for hosting web servers, database servers, mail servers, and other critical applications. CentOS is often preferred by organizations that require enterprise-grade features and support but want to avoid the costs associated with RHEL licenses.
   7. Community-Driven Development: CentOS is developed and maintained by a community of dedicated volunteers. The community ensures that CentOS remains aligned with the upstream RHEL project, incorporating updates, security patches, and bug fixes. The community-driven development model fosters collaboration, active participation, and community support forums.