2021 is officially over, followed by the popular Linux distribution for CentOS servers, with the latest version - CentOS 8 - reaching the end of its life yesterday December 31, 2021, meaning that, any server running on this version of CentOS will not receive any security updates anymore, and it must either move to CentOS Stream or find another alternative.
CentOS, or Community ENTerprise operating system, is a server-oriented Linux distribution derived from and compatible with Red Hat Enterprise Linux (RHEL) sources.
Red Hat Enterprise Linux (RHEL) is a Linux distribution developed by Red Hat Corporation (currently owned by IBM) for the commercial server market. Red Hat provides support and training to its corporate and individual clients for an annual fee. REHL itself is free to download and use, but without support, if you need support, you must pay for it.
With every change or update Red Hat makes at RHEL, the company releases the source code for it for free. The Linux community uses this source code to create packages with the same changes and updates and uses it to build an RHEL-compatible Linux distribution (this is called a re-distribution) under a different name since Red Hat prohibits its name from being used in projects derived from it.
These RHEL derivative distributions are either paid (in turn) like Oracle Linux or completely free like CentOS.
The first version of CentOS was released in May 2004, as a free, community-based, RHEL-compliant distribution, and in January 2014, Red Hat announced that it would sponsor the CentOS project, "helping to establish a platform well-suited to the needs of open-source developers that integrate technologies in and around the operating system". As a result of these changes, ownership of the CentOS trademarks was transferred to Red Hat, and most of the CentOS developers became employees of Red Hat, however the CentOS project, and development team, remained operating independently of the Red Hat Enterprise Linux team.
On January 8, 2019, Red Hat announced CentOS Stream, a Linux development platform and distribution, where members of the open-source community can contribute to Red Hat Enterprise Linux along with Red Hat developers. This means, that CentOS Stream is a test environment or distribution for testing packages and features that will be released in future RHEL versions.
In this sense, CentOS Stream is less stable than RHEL, and therefore less stable than CentOS, and since servers are sensitive environments, they need distribution as stable as possible, not an incomplete distribution that cannot be performance predicted in production environments.
Some call CentOS Stream a beta version of Red Hat Enterprise Linux, and see it as an exploitation of the Linux community, by Red Hat, to develop a more stable distribution and sell its support to get more revenue.
In December 2020, Red Hat announced the end of support for CentOS 8 on December 31, 2021, only about one year after its release, to focus on the development of CentOS Stream, and that there will be no new version of CentOS in the future, leaving the whole Linux community in a state of shock and to astonishment, and also to the companies and individuals who upgraded to the new CentOS release only a short time ago, while it was supposed to remain supported until 2029, and saw it as an attempt by Redhat to force them to move to RHEL and pay for support.
CentOS 7 version is still supported until June 30, 2024, so if you're still using this version you have two and a half years to think about how to upgrade your servers, but if you're using CentOS 8 and you look for an alternative, you have several free options like Rocky Linux, which is created by Greg Kurtzer, the co-founder of CentOS, or AlmaLinux. if you are not yet ready to upgrade your server and need more time, you can resort to paid services such as Tuxcare, which provide you with an Extended Lifecycle Support Service for CentOS 8 with the latest Kernel and critical package updates until December 2025, at $4.25 per OS image per month.