Linux knowledge Drip: Redhat and CentOS

Redhat has a paid commercial version and a free open source version, and the commercial version of the industry is called the Rhel (Red Hat Enterprise Linux) series,

This CentOS (Community ENTerprise Operating System) is compiled from the source code released by Rhel in accordance with the open source rules.

CentOS can be used instead of the commercial version of Rhel.

The difference between the two is that CentOS does not contain closed source code software.

CentOS is not a brand new Linux distribution, and if you talk about Red hat, everyone seems to have heard it. There is an enterprise version of the Red Hat family, which is Red Hat Enterprise Linux (hereafter known as Rhel) and CentOS is the clone version of this Rhel. Rhel is a Linux distribution used by many enterprises and needs to be paid for in red Hat to be used, as well as to receive paid service and technical support and version upgrades. CentOS can build a Linux system environment like Rhel, but there is no need to pay Red hat for any products and services, and there is no paid technical support or upgrade service.
Red Hat's products include Red Hat Linux (such as redhat8,9) and enterprise-issued versions of Red Hat Enterprise Linux, which are available and available for free via web FTP, but in 2003, Red Hat Linux stopped publishing and its projects were superseded by Fedora Project, which was released under the name Fedora Core and provided for free use by ordinary users. The Linux distribution of Fedora core is updated quickly, with a new release about half a year or so. The current version is Fedora Core 6, the Fedora Core test has a strong flavor, each release has new features added to it, the success of the results will be adopted in the release of the Dow Rhel. In spite of this, the frequent improvement of the unstable products for the enterprise is not the best choice, most enterprises will choose paid Rhel products (this has a deep meaning, such as the enterprise with Linux to make money, earn money to the enterprise, money in the circulation between enterprises, return to society, improve service standards, etc.).
Most of the packages that make up Rhel are distributed based on the GPL, which is what we often call open source software. Because of this, Red hat also follows this agreement and releases the packages that make up rhel, so long as it complies with the GPL, anyone can develop and publish it on the basis of the original software composition. CentOS is a Linux distribution that reproduces the composition of rhel on the basis of Rhel release. The clone version of Rhel is not just centos one, but White Box Enterprise Linux and Tao Linux and Scientific Linux (none of the others have ever heard of it, right?).
Although it is a Rhel clone, but not exactly the same, the said clone is 100% interchangeability (really?). However, there is no guarantee that the software corresponding to Rhel can work 100% on CentOS. and security bug fixes and software package upgrades for Rhel's paid service and technical support, a few days a few weeks a few months of delay also have (actually did not see how slow).
Features of CentOS
In the full name of CentOS, we can see the enterprise OS, which means that corporate systems, which are not enterprise-level systems, are the essential elements that can provide enterprise-class applications.
For example:
A stable environment
Support for long-term upgrade updates
A strong conservative nature
Large-scale systems are also capable of performing well
CentOS satisfies the above elements and satisfies the release version of the above elements and fedora. Fedora and CentOS are very similar, but for CentOS, Fedora offers more new features and software, as well as a quick release of updates, which adds a lot of effort to stability and management. The system environment required by the enterprise should be an efficient and stable system environment, a system environment that can be used for a long time after building, so the frequent update release system environment of Fedora does not correspond to the application of enterprise. On the other hand, CentOS is able to meet the needs of the above enterprises, in the numerous versions of Rhel clones, CentOS is very outstanding and excellent.
The difference between CentOS and RHEL
Why actually have CentOS? What is the relationship between CentOS and RHEL?
There are two ways in which RHEL is released. One is the binary distribution method, the other is the source code distribution mode.
Either way, you can get it for free (for example, download it from the Internet) and publish it again. But if you use their online upgrades (including patches) or consulting services, you'll have to pay.
Rhel has always provided the source code for the distribution, CentOS is the source of the RHEL release from the new compilation, the formation of a binary version can be used. Since the source code for LINUX is GNU, it is legal to get the source code from RHEL to the new binary. Just REDHAT is a trademark, so you have to remove REDHAT's trademark in the new release.
REDHAT's attitude to this distribution is: "We are not really against this distribution, the users who really pay us, they value not the system itself, but the business services we provide." ”
So, CentOS can get all the features of RHEL, even better software. However, CentOS does not provide commercial support to users and, of course, is not responsible for any business.
I'm gradually transferring my rhel to CentOS because I don't want to pay for Rhel upgrades. Of course, this is because I've had years of experience with UNIX, so it doesn't matter to me that RHEL's business support is there.
But if you are a purely business-oriented enterprise, then I suggest you buy the RHEL software and purchase the corresponding services. This will save you money on IT management and get professional services.
In a word, the choice of CentOS or RHEL depends on whether your company has the appropriate technical force.
Add:
1, CentOS also fixed some as bugs, such as the installation process package selection problem
2, CentOS added the Yum online upgrade
3.
CentOS-3.1 = as3-update1
CentOS-3.2 = As3-update2
CentOS-3.3 = As3-update3
CentOS-3.4 = As3-update4
CentOS-3.5 = As3-update5
CentOS-4.0 = AS4
CentOS-4.1 = as4-update1
4, the use of CentOS is completely legal, does not involve copyright issues
5. It is convenient to get CentOS, it provides more than 10 site images (HTTP/FTP), and BT mode (seed is provided perennial).
CentOS (Community ENTerprise Operating System) is one of the Linux distributions that compiles the source code of Red Hat Enterprise Linux (mainly to remove the Red Hat logo). Why does Red Hat tolerate this behavior of CentOS? CentOS Downloads source code from Red Hat Server, compiles, free of charge, and does not provide paid commercial support. Red hat releases the upgrade patches, and CentOS will release patches after hours or days. CentOS is perfectly legal, and Red hat is helpless, and its business is based on the open source model. But CentOS does continue to devour the Red Hat market, which is also observed on Google trends. From the current situation, the damage done by CentOS has not yet reached the point where red Hat has to change the business model. The advantage is that it forces red hat to innovate faster, always ahead of other Linux server distributions. The real victims of CentOS's great success are other distributions, such as Novell's Sles,ubuntu server. (Content transferred from the network)

Linux knowledge Drip: Redhat and CentOS