CentOS, also known as Community Enterprise Operating System, is a Linux distribution developed from the source code of Red Hat Enterprise Linux(RHEL). Initial release of CentOS was in May, 2014 through the source code made public by Red Hat and thus it aims to be functionally compatible(different from binary compatibility) with its upstream source RHEL with the exclusion of proprietary additions(branding, logos, etc.) and Red Hat support. There are many advantages of CentOS that have allegedly propelled it to have a bigger user base than RHEL & Fedora taken together. Some of these advantages are discussed below.
Stability Feature
When you are looking for a server distribution for your enterprise, the most important feature happens to be the stability of the operating system used. In India as well as elsewhere, CentOS happens to be in a league of its own when it comes to stability and thus server administration. Once you have your applications running on a server, you don't want to keep on changing your applications to workaround new software versions and constant updates that probably going to break your existing set-up. CentOS, unlike Fedora, provides an assured base that does not move that quickly and would not break when it gets updated. However, it does get security updates pretty fast so that the users do not have to wait with bated breath for such patches.
Functional Compatibility
As CentOS is developed with the RHEL source code, it does aspire to have functional & binary compatibility with it. This is quite helpful if in future you decide to move to a Red Hat supported package. Functional compatibility here generally refers to the aim of CentOS to have bug for bug compatibility, linking of the same libraries, to have same file lists in the package, etc. and at the same time keep on changing according to the environment it is used in independent of RHEL.
It must be clearly understood that functional compatibility discussed here is different than the binary as it is not possible to have 100% binary compatibility with RHEL because of the fact that the staged build system used by Red Hat allows it to create a package which is yet to be released multiple times into the staged build system. Hence, it is quite plausible that they have used those library versions that were not made public and therefore no compatibility in this regard could be achieved.
Community Backing
CentOS has a massive community of developers and Linux system administrators who work in conjunction to fix and discuss every possible bug, website related problems, updates, important announcements and other support issues. It is growing by the day and renowned community rebuilds such as Scientific Linux and others are also participating in the project.
Cost Aspect
RHEL being a commercial Linux distribution, comes under the proprietary license ambit and many enterprises may not be able to afford it. CentOS on the other hand is a freely distributed Linux distribution which has a pretty high compatibility with RHEL. In India, many server administrators choose CentOS over RHEL to take advantage of its free nature and huge supporting community.
