Understanding the CentOS release cycle

The CentOS release cycle is closely tied to its upstream source, Red Hat Enterprise Linux (RHEL), as CentOS is essentially a community-supported rebuild of RHEL. Here's an overview of the CentOS release cycle:

1. RHEL Release:

   • The CentOS release cycle begins with the release of a new version of RHEL by Red Hat.
   • RHEL typically follows a major release cycle, with new major versions being released every few years. For example, RHEL 7, RHEL 8, etc.

2. Rebuild Process:

   • After the release of a new version of RHEL, the CentOS development team starts the process of rebuilding the source code to create a compatible CentOS release.
   • The rebuild process involves removing Red Hat's trademarks and branding, as well as any proprietary components, and then rebuilding the source code to create a distribution that is functionally equivalent to RHEL.

3. Testing and Quality Assurance:

   • Once the rebuild process is complete, the CentOS team conducts extensive testing and quality assurance to ensure that the distribution is stable and reliable.
   • This testing phase helps identify and address any issues or compatibility issues that may have arisen during the rebuild process.

4. Release of CentOS:

   • After thorough testing and quality assurance, the CentOS team releases the new version of CentOS to the public.
   • CentOS releases typically coincide with the corresponding RHEL release, but they may lag behind by a few weeks or months due to the time required for the rebuild process and testing.

5. Updates and Maintenance:

   • After the initial release, CentOS continues to receive updates and maintenance releases to address security vulnerabilities, bug fixes, and other issues.
   • These updates are provided through the CentOS repositories and are made available to users via the package management system (yum or dnf).

6. Long-Term Support:

   • CentOS versions receive long-term support, with updates and security patches being provided for several years after the initial release.
   • The exact duration of support varies depending on the version, but CentOS typically provides support for at least 7-10 years for each major release.

7. End of Life (EOL):

   • Eventually, each CentOS release reaches its end-of-life (EOL) and is no longer supported by the CentOS project.
   • Users are encouraged to upgrade to a newer version of CentOS or migrate to an alternative distribution to continue receiving updates and support.