Red Hat Enterprise Linux

Red Hat Enterprise Linux (RHEL) is a commercial Linux distribution developed by Red Hat. Red Hat Enterprise Linux is released in server versions for x86-64, Power ISA, ARM64, and IBM Z and a desktop version for x86-64. Fedora Linux and CentOS Stream serve as its upstream sources. All of Red Hat's official support and training, together with the Red Hat Certification Program, focuses on the Red Hat Enterprise Linux platform.

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.

As Red Hat Enterprise Linux is heavily based on open-source software and its source code is available to the public, it is used as the basis for several third-party derivatives, including the commercial Oracle Linux and the community-supported Rocky Linux and AlmaLinux. Prior to June 2023, Red Hat published a subset of Red Hat Enterprise Linux's source code to the public in the form of modified build artifacts. Today, the complete source code for the major-version branch is available in the form of the CentOS Stream repositories. Source code for other release branches remains available to customers in the form of unmodified build artifacts.

Variants A Red Hat Enterprise Linux Server subscription is available at no cost for development purposes. Developers need to register for the Red Hat Developer Program and agree to its license terms. The free developer subscription was announced on March 31, 2016, and updated in January 2021 with less restrictive terms.

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 the 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.

In Red Hat Enterprise Linux 5 there are new editions that substitute former Red Hat Enterprise Linux AS/ES/WS/Desktop:

Red Hat Enterprise Linux Advanced Platform (former AS) Red Hat Enterprise Linux (former ES) (limited to two 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)

Red Hat had also announced its Red Hat Global Desktop Linux edition "for emerging markets".

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.

Relationship with Fedora Linux The Fedora Project provides the following explanation:

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.Originally, Red Hat sold boxed versions of Red Hat Linux directly to consumers and business through phone support. The Fedora Project began in 2002 as a set of community supported packages for Red Hat Linux. However, the six month release cycle of Red Hat Linux was too disruptive for business users and Red Hat wanted a more reliable revenue stream. In 2002 Red Hat began releasing Red Hat Enterprise Linux based on Red Hat Linux, but with a much more conservative release cycle and a subscription based support program. A year later, Red Hat discontinued the Red Hat Linux product line, merging it with the Fedora community packages and releasing the resulting Fedora distribution for free.

Fedora serves as the primary upstream for future major releases of RHEL: RHEL source code repositories are forked off the Fedora repository, and released after a substantial stabilization and quality assurance effort. The major-version stable release branch is built and released by the CentOS project under the name CentOS Stream. Each minor version of RHEL is a branch of CentOS Stream that gets ongoing bug fixes and security updates.

For example, CentOS Stream 9 was forked from Fedora in March, 2021 (shortly before the Fedora 34 release) and available on public mirrors in September, 2021. RHEL 9.0 was released in May, 2022.

The Fedora Project lists the following lineages for older Red Hat Enterprise releases:

Red Hat Linux 6.2/7 to Red Hat Linux Enterprise Edition 6.2E Red Hat Linux 7.2, 7.2A to Red Hat Enterprise Linux 2.1 Red Hat Linux 9 to Red Hat Enterprise Linux 3 Fedora Core 3 to Red Hat Enterprise Linux 4 Fedora Core 6 to Red Hat Enterprise Linux 5 Fedora 12, 13 to Red Hat Enterprise Linux 6 Fedora 19, 20 to Red Hat Enterprise Linux 7 Fedora 28 to Red Hat Enterprise Linux 8 Fedora 34 to CentOS Stream 9 to Red Hat Enterprise Linux 9 Fedora 40 to CentOS Stream 10 to Red Hat Enterprise Linux 10

In addition, the Fedora project publishes a set of packages for RHEL called the Extra Packages for Enterprise Linux (EPEL). EPEL packages can be expected to work in RHEL, but it is up to willing community members to maintain the packages and back port any upstream changes. As such, packages "may come and go" during the ten-year lifespan of the RHEL release and Red Hat support plans do not include resolving issues caused by EPEL packages.

Derivatives

Red Hat Enterprise Linux is derived from free and open source software. Until 2015, Red Hat made the source code to its enterprise distribution publicly available through its FTP website, though the inclusion of Red Hat trademarks prevented direct redistribution of the software. In 2015, Red Hat began publishing de-branded source code via git repositories on git.centos.org. Several groups used the source code to compile their own derivatives, typically with changes including 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 AlmaLinux, CentOS, MIRACLE LINUX, Oracle Linux, CloudLinux OS, Rocky Linux, Scientific Linux, StartCom Enterprise Linux, Pie Box Enterprise Linux, X/OS, Lineox, and Bull's XBAS for high-performance computing.

In 2023, Red Hat replaced the process that published code to git.centos.org in favor of the CentOS Stream git repositories. As required by its open-source licenses, the code for branched releases remains available to customers and developers, but the customer contract allows Red Hat to drop any customer who provides third-parties with access to subscription services, discouraging them from publishing source code artifacts. This led to AlmaLinux, one of the RHEL derivative Linux distributions, moving away from "1:1 bug for bug" compatibility to "application binary interface (ABI) compatible", while Oracle, SUSE, and CIQ (the company behind Rocky Linux) collaborated to form the Open Enterprise Linux Association (OpenELA) in order to provide "open and free Enterprise Linux (EL) source code".

Derivatives of Red Hat Enterprise Linux are free but do not get any commercial support or consulting services from Red Hat and lack software, hardware or security certifications from Red Hat. They also 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 RHEL 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. 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. Their competitor Oracle announced in November 2012 that they were releasing a RedPatch service, which allows public view of the RHEL kernel changes, broken down by patch.

Red Hat Enterprise Linux

Bron en licentie