Red Hat Enterprise Linux
Red Hat Enterprise Linux 6's default GNOME 2 desktop
|Company / developer||Red Hat, Inc.|
|Source model||Free and open source software (with exceptions)1|
|Initial release||February 22, 20002|
|Latest release||6.5, 5.10 / November 21, 2013, September 30, 2013|
|Marketing target||Commercial market (including for mainframes, servers, supercomputers)|
|Update method||Yum / PackageKit|
|Supported platforms||IA-32, x86-64; Power Architecture; S/390; z/Architecture3|
|Kernel type||Monolithic (Linux)|
|Default user interface||GNOME|
|License||Various free software licenses, plus proprietary binary blobs.1|
|Preceded by||Red Hat Linux|
Red Hat Enterprise Linux (RHEL) is a Linux distribution developed by Red Hat and targeted toward the commercial market. Red Hat Enterprise Linux is released in server versions for x86, x86-64, Itanium, PowerPC and IBM System z, and desktop versions for x86 and x86-64. All of Red Hat's official support and training and the Red Hat Certification Program centers around the Red Hat Enterprise Linux platform. Red Hat Enterprise Linux is often abbreviated to RHEL, although this is not an official designation.4
The first version of Red Hat Enterprise Linux to bear the name originally came onto the market as "Red Hat Linux Advanced Server". In 2003 Red Hat rebranded Red Hat Linux Advanced Server to "Red Hat Enterprise Linux AS", and added two more variants, Red Hat Enterprise Linux ES and Red Hat Enterprise Linux WS.
While Red Hat uses strict trademark rules to restrict free re-distribution of their officially supported versions of Red Hat Enterprise Linux,5 Red Hat freely provides the source code for the distribution's software even for software where this is not mandatory. As a result, several distributors have created re-branded and/or community-supported re-builds of Red Hat Enterprise Linux that can legally be made available, without official support from Red Hat. CentOS, Scientific Linux, and Oracle Linux aim to provide 100% compatibility with Red Hat Enterprise Linux (however besides their Red Hat Compatible Kernel note that Oracle also offers and advertises their non-100%-compatible Unbreakable Enterprise Kernel). There are also several other notable derivatives.
There are also "Academic" editions of the Desktop and Server variants. They are offered to schools and students, are less expensive, and are provided with Red Hat technical support as an optional extra. Web support based on number of customer contacts can be purchased separately.
It is often assumed the branding ES, AS, and WS stand for "Entry-level Server", "Advanced Server" and "Work Station", respectively. The reason for this is that the ES product is indeed the company's base enterprise server product, while AS is the more advanced product. However, nowhere on its site or in its literature does Red Hat say what AS, ES and WS stand for.
- Red Hat Enterprise Linux Advanced Platform (former AS)
- Red Hat Enterprise Linux (former ES) (limited to 2 CPUs)
- Red Hat Enterprise Linux Desktop with Workstation and Multi-OS option
- Red Hat Enterprise Linux Desktop with Workstation option (former WS)
- Red Hat Enterprise Linux Desktop with Multi-OS option
- Red Hat Enterprise Linux Desktop (former Desktop)
RHEL 4, 3, and prior releases had four variants:
- Red Hat Enterprise Linux AS for mission-critical/enterprise computer systems.
- Red Hat Enterprise Linux ES for supported network servers
- Red Hat Enterprise Linux WS for technical power user enterprise desktops for high-performance computing
- Red Hat Desktop for multiple deployments of single-user desktops for enterprises.
Originally, Red Hat sold support for versions of Red Hat Linux (Red Hat Linux Enterprise Edition 6.2E was essentially a version of Red Hat Linux 6.2/7 with different support levels.)9 Starting with RHEL 2.1 AS in 2002, Red Hat sold their first version of RHEL. It was based on Red Hat Linux, but used a much more conservative release cycle. Later versions included technologies from the Red Hat sponsored Fedora community distribution project. Red Hat Enterprise Linux release schedules do not follow that of Fedora (around 6 months per release) but are more conservative (2 years or more).
Fedora serves as upstream for future versions of RHEL. RHEL trees are forked off the Fedora repository, and released after a substantial stabilization and quality assurance effort.10 For example, RHEL 6 was forked from Fedora at the end of 2009 (approximately at the time of the Fedora 12 release) and released more or less together with Fedora 14. By the time RHEL 6 was released, many features from Fedora 13 and 14 had already been backported into it. The Fedora Project lists the following lineages for older Red Hat Enterprise releases:10
- Red Hat Linux 6.2/7 → Red Hat Linux Enterprise Edition 6.2E
- Red Hat Linux 7.2 → Red Hat Enterprise Linux 2.1
- Red Hat Linux 10 beta 1 → Red Hat Enterprise Linux 3
- Fedora Core 3 → Red Hat Enterprise Linux 4
- Fedora Core 6 → Red Hat Enterprise Linux 5
- Fedora 12, 13 → Red Hat Enterprise Linux 610
- Fedora 19 → Red Hat Enterprise Linux 711
(Note about Fedora Core 1 and Red Hat Enterprise Linux 3: Red Hat released Red Hat Linux 10 beta 1, then took two forks from that codebase to seed both Fedora Core 1 and Red Hat Enterprise Linux 3 beta releases. There was some cross-pollination between the two up until shortly before the first production RHEL 3 release. Therefore, both FC1 and RHEL3 came from a common fork of RHL10beta1.)
In addition, the Fedora project includes Extra Packages for Enterprise Linux (EPEL), a community-provided set of packages for RHEL going beyond the ones that Red Hat selected for inclusion in its supported distribution.
“Both Fedora and Red Hat Enterprise Linux are open source. Fedora is a free distribution and community project and upstream for Red Hat Enterprise Linux. Fedora is a general purpose system that gives Red Hat and the rest of its contributor community the chance to innovate rapidly with new technologies. Red Hat Enterprise Linux is a commercial enterprise operating system and has its own set of test phases including alpha and beta releases which are separate and distinct from Fedora development.”12
Originally, Red Hat's enterprise product, then known as Red Hat Linux, was made freely available to anybody who wished to download it, while Red Hat made money from support. Red Hat then moved towards splitting its product line into Red Hat Enterprise Linux which was designed to be stable and with long-term support for enterprise users and 'Fedora' as the community distribution and project sponsored by Red Hat. The use of trademarks prevents verbatim copying of Red Hat Enterprise Linux.
Since Red Hat Enterprise Linux is based completely on free and open source software, Red Hat makes available the complete source code to its enterprise distribution through its FTP site to anybody who wants it. Accordingly, several groups have taken this source code and compiled their own versions of Red Hat Enterprise Linux, typically with the only changes being the removal of any references to Red Hat's trademarks and pointing the update systems to non-Red Hat servers. Groups which have undertaken this include CentOS (the 8th most popular Linux distribution as of November 2011),13 Oracle Linux, Scientific Linux, White Box Enterprise Linux, StartCom Enterprise Linux, Pie Box Enterprise Linux, X/OS, Lineox, and Bull's XBAS for high-performance computing.14 All provide a free mechanism for applying updates without paying a service fee to the distributor.
Rebuilds of Red Hat Enterprise Linux are free but do not get any commercial support or consulting services from Red Hat and lack any software, hardware or security certifications. Also, the rebuilds do not get access to Red Hat services like Red Hat Network.
Unusually, Red Hat took steps to obfuscate their changes to the Linux kernel for 6.0 by not publicly providing the patch files for their changes in the source tarball, and only releasing the finished product in source form. Speculation suggested that the move was made to affect Oracle's competing rebuild and support services, which further modifies the distribution. This practice however, still complies with the GNU GPL since source code is defined as "[the] preferred form of the work for making modifications to it", and the distribution still complies with this definition.15 Red Hat's CTO Brian Stevens later confirmed the change, stating that certain information (such as patch information) would now only be provided to paying customers to make the Red Hat product more competitive against the growing number of companies offering support for products based on RHEL. CentOS developers had no objections to the change since they do not make any changes to the kernel beyond what is provided by Red Hat.16
A number of commercial vendors use Red Hat Enterprise Linux as a base for the operating system in their products. Two of the best known are the Console Operating System in VMware ESX Server and Oracle Linux respin.
- Red Hat Enterprise Linux 2.1 AS (Pensacola), 26 March 2002. Uses Linux 2.4.9-e.317
- Update 1, 14 February 2003 (kernel 2.4.9-e.12)17
- Update 2, 29 May 2003 (kernel 2.4.9-e.24)17
- Update 3, 19 December 2003 (kernel 2.4.9-e.34)17
- Update 4, 21 April 2004 (kernel 2.4.9-e.40)17
- Update 5, 18 August 2004 (kernel 2.4.9-e.49)17
- Update 6, 13 December 2004 (kernel 2.4.9-e.57)17
- Update 7, 28 April 200518
- Red Hat Enterprise Linux 2.1 ES (Panama), May 2003citation needed
- Red Hat Enterprise Linux 3 (Taroon), 22 October 2003. Uses Linux 2.4.21-417
- Update 1, 16 January 2004 (kernel 2.4.21-9)17
- Update 2, 12 May 2004 (kernel 2.4.21-15)17
- Update 3, 3 September 2004 (kernel 2.4.21-20)17
- Update 4, 12 December 2004 (kernel 2.4.21-27)17
- Update 5, 18 May 2005 (kernel 2.4.21-32)17
- Update 6, 28 September 2005 (kernel 2.4.21-37)17
- Update 7, 17 March 2006 (kernel 2.4.21-40)17
- Update 8, 20 July 2006 (kernel 2.4.21-47)17
- Update 9, 15 June 2007 (kernel 2.4.21-50)17
- Red Hat Enterprise Linux 4 (Nahant), 15 February 2005. Uses Linux kernel 2.6.9-517
- 4.1, also termed Update 1, 8 June 2005 (kernel 2.6.9-11)17
- 4.2, also termed Update 2, 5 October 2005 (kernel 2.6.9-22)17
- 4.3, also termed Update 3, 12 March 2006 (kernel 2.6.9-34)17
- 4.4, also termed Update 4, 10 August 2006 (kernel 2.6.9-42)17
- 4.5, also termed Update 5, 1 May 2007 (kernel 2.6.9-55)17
- 4.6, also termed Update 6, 15 November 2007 (kernel 2.6.9-67)17
- 4.7, also termed Update 7, 29 July 2008 (kernel 2.6.9-78)17
- 4.8, also termed Update 8, 19 May 2009 (kernel 2.6.9-89)17
- 4.9, also termed Update 9, 16 February 2011 (kernel 2.6.9-100)17
- Red Hat Enterprise Linux 5 (Tikanga), 14 March 2007. Uses Linux kernel 2.6.18-817
- 5.1, also termed Update 1, 7 November 2007 (kernel 2.6.18-53)17
- 5.2, also termed Update 2, 21 May 2008 (kernel 2.6.18-92)17
- 5.3, also termed Update 3, 20 January 2009 (kernel 2.6.18-128)17
- 5.4, also termed Update 4, 2 September 2009 (kernel 2.6.18-164)17
- 5.5, also termed Update 5, 30 March 2010 (kernel 2.6.18-194)17
- 5.6, also termed Update 6, 13 January 2011 (kernel 2.6.18-238)17
- 5.7, also termed Update 7, 21 July 2011 (kernel 2.6.18-274)17
- 5.8, also termed Update 8, 20 February 2012 (kernel 2.6.18-308)17
- 5.9, also termed Update 9, 7 January 2013 (kernel 2.6.18-348)17
- 5.10, also termed Update 10, 1 October 2013 (kernel 2.6.18-371)17
Red Hat Enterprise Linux 6 was forked from Fedora 12 and contains many backported features from Fedora 13 and 14.
- Red Hat Enterprise Linux 6 (Santiago), 10 November 2010 Uses Linux kernel 2.6.32-7117
- 6.1, also termed Update 1, 19 May 2011 (kernel 2.6.32-131)17
- 6.2, also termed Update 2, 6 December 2011 (kernel 2.6.32-220)17
- 6.3, also termed Update 3, 20 June 2012 (kernel 2.6.32-279)17
- 6.4, also termed Update 4, 21 February 2013 (kernel 2.6.32-358)17
- 6.5, also termed Update 5, 21 November 2013 (kernel 2.6.32-431)17
- Red Hat Enterprise Linux 7 (Maipo) will be based on Fedora 19 and upstream Linux kernel 3.10, with the first beta announced on 11 December 2013.1119
The life cycle of Red Hat Enterprise Linux is 10 years for versions 3 and 4, while it spans 13 years for more recent versions 5 and 6. The life cycle comprises several phases of varying length with varying degrees of support. During the first phase ("Production 1"), Red Hat provides full support and updates software and hardware drivers. In later phases ("Production 2" and "Production 3") only security fixes are provided and support for new hardware is gradually reduced.20
In the last three years of the life cycle ("Extended Life Phase") critical and security-related fixes are only provided to customers who pay an additional subscription ("Extended Lifecycle Support Add-On") which is available for RHEL3/4 only and covers a limited number of packages.21
|Version||Release Date||End of Production 1 Phase||End of Production 2 Phase||End of Production 3 Phase||End of Extended Life Phase|
|Old version, no longer supported: Red Hat Enterprise Linux 2.1||26 March 2002 (AS)
1 May 2003 (ES)
|30 November 2004||31 May 2005||31 May 200922||N/A|
|Old version, no longer supported: Red Hat Enterprise Linux 3||23 October 2003||20 July 2006||30 June 2007||31 October 201023||30 January 2014|
|Older version, yet still supported: Red Hat Enterprise Linux 4||14 February 2005||31 March 2009||16 February 2011||29 February 2012||28 February 2015|
|Older version, yet still supported: Red Hat Enterprise Linux 5||15 March 2007||8 January 2013||31 January 2014||31 March 2017||Q1 2020|
|Current stable version: Red Hat Enterprise Linux 6||10 November 2010||Q2 2016||Q2 2017||30 November 2020||Q4 2023|
|Future release: Red Hat Enterprise Linux 7||Undisclosed24||Undisclosed||Undisclosed||Undisclosed||Undisclosed|
- "Explaining Why We Don't Endorse Other Systems". the Free Software Foundation. Retrieved March 13, 2011.
- Red Hat Press Releases at the Wayback Machine (archived March 4, 2001)
- "Supported Architectures". Retrieved 2010-11-21.
- "Tips and tricks: How do I properly refer to Red Hat Enterprise Linux 2.1, Red Hat Enterprise Linux 3, Red Hat Enterprise Linux 4 and Red Hat Enterprise Linux 5 in documentation and when conversing with fellow users and customers?". redhatmagazine.com. 2008-02-04. Retrieved 2008-06-25.
- "ESR: "We Don't Need the GPL Anymore"". onlamp.com. Retrieved 2008-03-04.
- "Moving to Red Hat Enterprise Linux 5". Red Hat. Retrieved 2009-12-02.
- "Red Hat Enterprise Linux Server Version Comparison Chart". Red Hat. Retrieved 2009-12-02.
- "Red_Hat_Global_Desktop_Linux:_The_Best_Kept_Secret?". linuxtoday.com. Retrieved 2008-03-04.
- "Fedora project wiki, History of Red Hat Linux". fedoraproject.org. Retrieved 2010-05-23.
- "Fedora project wiki, Red Hat Enterprise Linux History". fedoraproject.org. Retrieved 2010-06-08.
- "Red Hat Announces Availability of Red Hat Enterprise Linux 7 Beta". Red Hat. 2013-12-11. Retrieved 2013-12-11.
- "Fedora project wiki, the difference between Fedora and RHEL". fedoraproject.org. Retrieved 2010-05-23.
- "Linux Distributions - Facts and Figures". distrowatch.com. Retrieved 2008-03-04.
- SLURM at CEA
- "Controversy surrounds Red Hat's "obfuscated" source code release". The H. Retrieved 12 March 2011.
- "Red Hat defends changes to kernel source distribution". The H. Retrieved 12 March 2011.
- "Red Hat Enterprise Linux Updates and Related Kernel Versions". Red Hat. Retrieved 2012-05-16.
- "redhat-release-as-2.1AS-121.src.rpm". Red Hat. Retrieved 2012-05-16.
- "2013 Red Hat Summit". See for example this presentation.
- "Red Hat Enterprise Linux Life Cycle". Access.redhat.com. Retrieved 2014-04-11.
- "Enterprise Linux Extended Lifecycle Support Add-On". Red Hat. Retrieved 2014-02-12.
- "Red Hat Enterprise Linux Errata Support Policy". Red Hat. Archived from the original on 2010-04-05. Retrieved 2012-08-11.
- "Red Hat Enterprise Linux 3 - End Of Life". Red Hat. Retrieved 2010-01-12.
- Vaughan-Nichols, Steven J. (June 17, 2013). "Red Hat Enterprise Linux 7 software stack still under wraps". ZDNet. Retrieved October 9, 2013.
- Jang, Michael H. (2007). RHCE Red Hat Certified Engineer Linux Study Guide (RHEL 5). New York: McGraw-Hill. ISBN 978-0-07-226454-8.
- Ghori, Asghar (2009). Red Hat Certified Technician & Engineer (RHEL 5). Reston: Global Village Publishing. ISBN 978-1-61584-430-2.
- Fox, Tammy (2007). Red Hat Enterprise Linux 5 Administration Unleashed. Indianapolis, Ind.: Sams. ISBN 978-0-672-32892-3. OCLC 137291425.
- McCarty, Bill (2004). Learning Red Hat Enterprise Linux and Fedora. Sebastopol, CA: O'Reilly. ISBN 978-0-596-00589-4. OCLC 55130915.
- Negus, Christopher (2008). Fedora 9 and Red Hat Enterprise Linux Bible. Indianapolis, Ind.: Wiley. ISBN 978-0-470-37362-0. OCLC 222155845.
- Sobell, Mark G. (2008). Practical Guide to Fedora and Red Hat Enterprise Linux. Upper Saddle River, NJ: Prentice Hall. ISBN 978-0-13-714295-8. OCLC 216616647.
- Collings, Terry (2005). Red Hat Enterprise Linux 4 For Dummies. Hoboken, N.J.: Wiley. ISBN 978-0-7645-7713-0. OCLC 58973830.
- Petersen, Richard (2005). Red Hat Enterprise Linux & Fedora Core 4: The Complete Reference. London: McGraw-Hill. ISBN 978-0-07-226154-7. OCLC 62293551.
- Official website
- Brian Stevens, CTO and vice president of engineering, Red Hat on why Red Hat Enterprise Linux is "The Business OS for Flexibility and Value"
- Red Hat Enterprise Linux at DistroWatch