CentOS (Community ENTerprise Operating System) was a popular, free, and open-source Linux distribution derived from the sources of Red Hat Enterprise Linux (RHEL). While the original CentOS project has evolved, its legacy and influence remain significant in the Linux world. Here’s a comprehensive overview, covering its history, features, current state, and alternatives:
1. History & Evolution
- Early Days (2003-2020): CentOS began as a project to provide a free rebuild of RHEL. RHEL is a commercially supported Linux distribution known for its stability and long-term support. CentOS aimed to offer the same functionality without the subscription cost. It was a favorite among server administrators, developers, and those needing a reliable platform.
- CentOS Stream (2020 – Present): In December 2020, Red Hat announced a significant shift in the CentOS project. The traditional, rebuild-focused CentOS Linux distribution was discontinued. Instead, CentOS Stream was introduced.
- CentOS Stream is a rolling-release distribution that serves as the upstream development branch for future RHEL releases. This means it receives updates more frequently and is essentially a “preview” of what will eventually become RHEL.
- This change was controversial, as many users relied on CentOS Linux for its stability and binary compatibility with RHEL. The shift to a rolling release made it less suitable for production environments where predictability is crucial.
- Rocky Linux & AlmaLinux (2020 – Present): In response to the CentOS Stream change, two community-driven projects emerged:
- Rocky Linux: Founded by Gregory Kurtzer, one of the original founders of CentOS. Rocky Linux aims to be a true, bug-for-bug compatible rebuild of RHEL.
- AlmaLinux: Created by CloudLinux Inc., AlmaLinux also strives to be a binary-compatible alternative to RHEL.
2. Key Features (Historically – CentOS Linux 7/8)
- Stability: CentOS Linux was renowned for its stability, inheriting it from RHEL. It was designed for long-term operation with minimal downtime.
- Security: Regular security updates were provided, ensuring a secure operating system.
- Long-Term Support (LTS): CentOS Linux releases were supported for 10 years, providing a predictable lifecycle for deployments. (This is a key difference from CentOS Stream).
- Compatibility: Binary compatibility with RHEL meant that software and applications built for RHEL generally ran on CentOS without modification.
- Package Management: Used the
yum(Yellowdog Updater, Modified) package manager (later replaced bydnfin CentOS 8) for installing, updating, and removing software. - Community Support: A large and active community provided support through forums, mailing lists, and other channels.
- Free and Open Source: CentOS Linux was completely free to use, distribute, and modify.
- Server Focus: While usable as a desktop, CentOS was primarily geared towards server applications.
3. CentOS Stream – Current State
- Rolling Release: CentOS Stream receives frequent updates, making it more cutting-edge but potentially less stable than the traditional CentOS Linux.
- Upstream for RHEL: It’s the development platform for future RHEL releases. Features and changes are tested in CentOS Stream before being incorporated into RHEL.
- Suitable for:
- Developers who want to test new features.
- Users who don’t require the absolute stability of RHEL.
- Those who want to contribute to the development of RHEL.
- Not Suitable for:
- Production environments requiring long-term stability and binary compatibility with older RHEL versions.
- Users who need a predictable, unchanging operating system.
4. Alternatives to CentOS Linux (Post-Discontinuation)
- Rocky Linux: The most direct replacement for CentOS Linux. It aims for 1:1 binary compatibility with RHEL. Highly recommended for those who need a stable, RHEL-compatible server OS. https://rockylinux.org/
- AlmaLinux: Another excellent RHEL rebuild, also striving for binary compatibility. Backed by CloudLinux Inc. https://almalinux.org/
- Oracle Linux: A free (and commercially supported) Linux distribution based on RHEL. Oracle provides its own updates and support. https://www.oracle.com/linux/
- Red Hat Enterprise Linux (RHEL): The commercial distribution that CentOS originally mirrored. Requires a subscription. https://access.redhat.com/products/red-hat-enterprise-linux/
- Debian: A highly stable and widely used Linux distribution. Different package management system (
apt) than CentOS. https://www.debian.org/ - Ubuntu Server: Another popular Linux distribution, known for its ease of use. Also uses
apt. https://ubuntu.com/server
5. Where to find more information
- CentOS Stream: https://www.centos.org/centos-stream/
- Rocky Linux: https://rockylinux.org/
- AlmaLinux: https://almalinux.org/
- Red Hat: https://www.redhat.com/
In conclusion
The CentOS landscape has changed dramatically. While CentOS Stream continues as a rolling-release development platform, the traditional CentOS Linux is no longer available. Rocky Linux and AlmaLinux have successfully filled the void, offering stable, RHEL-compatible alternatives for those who need a reliable server operating system. The best choice for you depends on your specific needs and priorities. If you need a stable, predictable, and RHEL-compatible OS, Rocky Linux or AlmaLinux are excellent options. If you want to test the latest features and contribute to RHEL development, CentOS Stream might be a good fit.