CentOS is a popular open-source operating system maintained and developed by a large community of people. The core of the OS uses a Linux Kernel and builds upon the source code of Red Hat Enterprise Linux or RHEL ( A Linux distribution developed by Red Hat for the commercial market.)
CentOS itself is a Linux Distribution. Now the question is what is Linux Distribution or Distro?
Let me explain, a Linux distribution is an Operating System made from a software collection that is based upon the Linux kernel and has a package management system.
In order to use the Linux-based environment users usually choose a Linux distribution according to their needs. They are basically three types an embedded system, a Personal computer, and a supercomputer.
The Community Enterprise Operating System or Centos is functionally compatible with Red Hat Enterprise Linux (RHEL).
It’s completely free software means you can download, use, and even modified it according to your need without paying a single penny. And it’s a Linux-based OS so, you don’t have to worry about the security.
CentOS is very much used by small companies and startups because it’s very stable and included all the features of Redhat Enterprise Linux. The package management system is similar to RHEL so most of the packages and applications are work seamlessly in CentOS.
CentOS originated from CAOS Linux, an RPM( free and open-source package management system) based on Linux distribution started by Gregory Kurtzer in 2002.
It was launched in 2004 and is distributed under the GNU General Public License (GNU GPL). It is a stable, predictable, and easy-to-use Linux distribution, with a growing community behind it.
In June 2006, David Parsley, the primary developer of Tao Linux (another RHEL clone) joined the Centos project, and all the Tao Linux users are migrated to centos with a yum update( command-line package-management utility for Linux).
Next three years, there are various things going on within the project. The founder Lance Davis had disappeared but later in 2009 the centos team founded him and obtained the centos.info and centos.org domains.
In July 2010, CentOS overtook Debian to become the most popular Linux distribution for web servers and acquired the 30% server market share.
Red Hat Enterprise Linux announced to sponsored CentOS project in 2014 and their main aim is to help the developers who created this wonderful platform and integrated new technologies within the OS.
A new CentOS governing board was also established. From now on Redhat take care of all the CentOS developers but they continue to work on open source project and operates separately from the Red Hat Enterprise Linux team.
But In December 2020, Red Hat announced the discontinuation of the CentOS project and the latest Centos Linux 8 support ends on December 31st, 2021.
CentOS would be replaced by CentOS Stream, an upstream development platform for Red Hat Enterprise Linux.
Design and Releases:
CentOS is very similar to Red hat Linux because it uses the same source code. Although the OS is almost identical the branding and logos are different from RHEL because Redhat doesn’t allow them to use those for distribution purposes.
You can use CentOS for free and also get the technical support provided by the community via official mailing lists, web forums, and chat rooms.
Red Hat employs most of the CentOS head developers, the CentOS Project itself relies on donations from users and organizational sponsors.
The first CentOS version 2 was released in May 2004, it was forked from RHEL version 2.1AS. Similarly version 3,4,5,6 released on 2004,2005, 2007 and 2011.
With every release, they follow a fixed pattern and strategy. A full version was released in two parts, a minor and major release.
The minor versions are backward compatible and the major ones having incompatible API changes in the database.
Since mid-2006 starting with RHEL version 4.4, which is formally known as Red Hat Enterprise Linux 4.0 update 4, Red Hat has adopted a version-naming convention identical to that used by CentOS (for example, RHEL 4.5 or RHEL 6.5).
On 7th July 2014 CentOS officially released CentOS version 7.0.
CentOS versions are based on each equivalent RHEL version. So, each CentOs version is named under the same version number and timestamp as its Red Hat Enterprise Linux equivalent.
The timestamp of each version corresponds to the year and month of the equivalent version released by Red Hat. For instance, version 8 of CentOS is named “CentOS 8.0-1905” because RHEL 8.0 was released in May 2019
CentOS 4 had been supported for seven years and version5, 6, and 7 will be maintained for up to 10 years, as these are based on RHEL.
Latest version: CentOS 8.0-1905
CentOS 8 is the latest major version, released in September 2019. It fully supports the modern system architecture based on the Linux 4.18 kernel.
Minor versions of CentOS Linux 8 have been released later on:
- CentOS 8.1-1911: released on January 15, 2020. RHEL 8.1 was released on November 5, 2019.
- CentOS 8.2-2004: released on June 15, 2020. RHEL 8.2 was released on April 28, 2020.
However, as mentioned before, CentOS 8 end-of-life will arrive on December 31, 2021. As CentOS Linux will be replaced by CentOS Stream.
CentOS 3 supports Intel Itanium-based processors 64-bit architecture.
CentOS 4 has IA-64 bit support, SPRAC (Reduced instruction set computing-based architecture) beta support, 32-bit PowerPC (Apple and Mac) beta support, and Alpha support.
Later version 5 supported IBM Mainframe computers and was very popular in server architecture.
IA-32 bit without Physical Address Extention supported by Centos 6. Later both X86 and X64 support were included.
ARM 64-bit architecture like ARMv7hl and AArch64, IA-32 architecture, and Power ISA ( Openpower architecture led by IBM) all are supported by CentOS 7.
The latest CentOS 8 fully supports the x86-64, POWER8, and 64-bit ARM architectures.
CentOS Linux and CentOS Stream:
CentOS Linux is an operating system mostly used in the web servers of enterprises and organizations. It’s a well reputed and dependable choice for any commercial use and ranked third among the world-famous three distros after Ubuntu and Debian.
Sadly CentOS 8 is the last release of this category as Red hat planning to discontinue it. They replaced it with CentOS Stream. This shift means that the life cycle of the latest CentOS distribution, released last year, will end on December 31, 2021.
The good news is CentOS Linux 7 distribution will continue, as scheduled, until 2024. The timeline is summarized as follows:
- CentOS Linux 7 distribution: updates until June 30, 2024.
- CentOS Linux 8 distribution: updates until December 31, 2021.
- CentOS Stream 9 launch date: Q2 2021 (as part of the RHEL 9 development)
On the other hand, CentOS Stream is an Upstream development of Red Hat Enterprize Linux.
This distribution will be useful for the community, as a stable ABI/API for testing and development. It can be downloaded, used, studied, modified, and redistributed for free (with the exception of CentOS trademarks owned by Red Hat).
This platform aims to take advantage of open-source innovation for shaping upcoming stable RHEL releases.
Most of the features are similar to Red Hat but very important as well. Some are …
A committed and expert community of developers keeps the OS updated all the time and ensures compatibility both with new software and old applications. Besides, core developers, there is a wonderful volunteer community that works from all over the world.
The system administrators, network administrators, Linux enthusiasts, etc — that test releases, rebuild updates, and provide support.
Performance and Availability:
KVM ( Kernel-Based Virtual Machine) is used for virtualization and offers great performance and high availability.
CentOS includes the kernel extension SELinux (Security-Enhanced Linux) which enhanced the security of the system. Also, a world-class security team proactively detects vulnerabilities and guarantees a high level of security.
Update and Support:
CentOS versions are regularly updated, approximately every 6 months, and are supported for 10 years.
So If you want an enterprise-level operating system and don’t want to spend lots of money at the beginning then CentOS might be a great choice for you. It is a free-to-use OS where you get all the RHEL features, application, and security support without any subscription fee.
But with the discontinuation of Centos 8 in 2021 RHEL introduced CentOS Stream as an upstream source of RHEL. This means that new features will be introduced into CentOS Stream, where the bugs are fixed and updates are coming frequently.
It’s more like a business move where RedHat introduces instability into CentOS and strengthens their own flagship distro.
So, it’s completely up to you whether you use the CentOS Stream or go with the Red Hat Enterprise Linux. If you want to give it a try then here is the link, Download Centos from here.