What are CentOS and CentOS Stream and History

CentOS (Community ENTerprise Operating System) also widely referred to as CentOS Linux, is a free and open-source community-developed Linux distribution that was based on RHEL. It is a no-cost RHEL build that was popular for handling production workloads and also as a desktop distribution.

For a long time, CentOS enjoyed a good run winning the adulation of thousands of Linux users until its sudden demise on December 31, 2021. CentOS 8 was unilaterally discontinued by RedHat in favor of CentOS Stream which is the upstream and current development branch of RHEL, thus marking the end of support for the CentOS Project.

Differences Between CentOS and CentOS Stream

Before we go any further, let us take a minute or two and explore the differences between these two operating systems.

CentOS Linux is a rebuild of Red Hat Enterprise Linux (RHEL), and hence a downstream from RHEL. On the other hand, CentOS Stream is a continuous delivery distribution and development branch of RHEL.

CentOS Stream 9 tracks ahead of the next minor release of RHEL 9. Packages being introduced to CentOS Stream are rigorously tested and checked to ensure that they meet the required standards for inclusion n RHEL.

CentOS Linux is a point release, which means that it adds minor changes such as bug fixes and security enhancements to its next release. For example, CentOS 8.3.2011 is a rebuild of CentOS 8.3 which was released in 2020. On the other hand, CentOS Stream is continually being developed and is currently the development branch of RHEL.

Since it is continually developed, CentOS Stream provides the latest software and system updates which are tested before they are ported to RHEL.

With CentOS Linux, smaller batches of updates are introduced to each successive release, and hence you might have to wait a while to get the latest modules or packages. In a nutshell, the frequency of updates in CentOS Linux is low.

History of CentOS Linux

Let us now switch gears and explore the evolution of CentOS Linux, which was originally founded in 2002 as a build of CaOS Linux which was an RPM-based Linux distribution under the stewardship of Gregory Kurtzer.

CentOS 3.0 (2004)

CentOS 3.0 was the first official CentOS release that was made available to the public. It was released on March 19, 2004, and was supported until October 31, 2010.

CentOS 4 (2005)

CentOS 4.0 took over from CentOS 3 and was released on March 9, 2005. This was supported until February 29, 2012.

CentOS 5.0 (2007)

CentOS 5.0 was released on April 12, 2007, and marked the beginning of a 10-year support lifecycle for CentOS by RHEL. CentOS 4 was supported for 7 years, but CentOS 5 heralded a new era with a 10-year maintenance period. As such, CentOS 5 was supported until March 31, 2017.

CentOS 6 (2011)

CentOS 6 was released on July 10, 2011, and was maintained up to November 30, 2020.

Notable improvements included:

  • YUM version 2 was used.
  • It supported Perl 5.10.1, PHP 5.3, and Python 2.6.6 to mention a few packages.
  • X.Org 7.4 server was introduced as the default display manager for the GNOME desktop.
  • It supported multi-queue networking, wireless networking, IPv6, and Netlabel kernel subsystem.

CentOS 7.0 (2014)

CentOS 7 was released on July 7, 2014, starting with CentOS 7.0-1406, including a third section in the version number denoting the month stamp of the release. In addition, CentOS started maintaining a major and minor release both of which are based on RHEL. For example, CentOS 7.0-1406 is based on RHEL 7.

CentOS 7 was built from sources hosted at git.centos.org. CentOS 7 brought major improvements including:

  • Support for Linux containers.
  • Kernel updated to 3.10.0.
  • XFS is the default filesystem.
  • Systemd replaced the old SysV init.
  • Introduction of LVM-snapshots with ext4 and XFS filesystems.
  • OpenJDK-7 as the default JDK.
  • 3D Graphics drivers and Open VMware Tools drivers out of the box.
  • In-Place Upgrade from 6.5 to 7.0.

CentOS 7 is currently the only CentOS version that is still supported and actively maintained. It will receive support until June 30, 2024.

CentOS 8.0 (2019)

On September 24, 2019, CentOS officially released CentOS 8.0 included remarkable improvements as follows

  • Linux kernel 4.18.
  • Improvements n QEMU-KVM with the introduction of sandboxing features.
  • Podman replaced Docker as the de-facto application for deploying and managing containers alongside buildah and Skopeo.
  • DNF (Dandified Yum) replaced YUM as the default package manager.
  • GNOME 3.28 was the default Desktop environment with Wayland as the display manager.
  • Nftables replaced IPtables as the primary framework for configuring the system’s firewall.
  • Expanded support for numerous architectures including x86_64, IBM Power, IBM Z, and 64-bit for ARM.
  • New software packages include Apache HTTP 2.4, Python 3.6, Ruby 2.5, Perl 5.26, MySQL 8.0, PostgreSQL 10, and Redis 6.
  • For developers, CentOS 8.0 shipped with Mercurial 4.8, Git 2.18, and Subversion 1.10.

Sadly, CentOS 8 never lived to achieve its full potential and was abruptly discontinued by RedHat on December 31, 2021, to pave way for CentOS Stream. This marked the end of CentOS Linux.

CentOS Stream

As previously mentioned, CentOS Stream is a continually developed distribution that is now the upstream and developmental release for Red Hat Enterprise Linux. It’s positioned as a midstream between Fedora Linux and RHEL and provides the latest software packages.

CentOS Stream was introduced as a preview version to RHEL. Simply put, it’s a development rebuild of RHEL and thus simplifies contribution to RHEL development. CentOS Stream is ideal for users who want to test the viability of using RHEL on their servers at no cost.

As to whether or not it can replace CentOS Linux, CentOS Stream is not considered stable enough for enterprise support. Since it is continually updated, there are chances that an update can interfere with your production workload in the event of an updated library or even having a package that is buggy and not optimized for best performance.

If you are transitioning from CentOS Linux in search of a stable and no-cost build of RHEL that can handle enterprise-grade workloads, Rocky Linux and AlmaLinux are recommended.

CentOS Stream 9 is the current version of CentOS Stream and was released on December 3, 2021.

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