After an upstream project has released a newer version of a package when will the package on a Red Hat Enterprise Linux system be updated to this version?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux

Issue

  • Package provided in Red Hat Enterprise Linux (RHEL) is not latest, when the latest package will be available?
  • OpenSSL package provided in Red Hat Enterprise Linux 4 is old, when new package will be released?
  • The Python version that comes with RHEL 5.4 is way out of date.
  • How can I install a later upstream kernel on RHEL?
  • Is there a supported version of ELRepo's kernel-ml or kernel-lt packages?
  • How does RHEL packaging versioning and package versions work?

Resolution

When looking at capabilities of RHEL packages compared to later upstream versions, it is incorrect to focus on version number, instead the focus should be on the specific feature or bug/security fix that the later upstream software provides.

For example, the SO_REUSEPORT socket option was added to upstream Linux kernel v3.9. However, it is not necessary to use kernel v3.9 or RHEL 7 to take advantage of this feature, as it is available in RHEL 6.5 and later due to proactive feature enhancement by Red Hat.

This process is explained more thoroughly in the Root Cause section below.

Root Cause

Red Hat Enterprise Linux is a maintained collection of many different software components which are drawn from the wider open source software community.

At the time that a RHEL major version is released, a particular version of each of the software component has been selected and run through a rigorous testing and Quality Engineering cycle to improve its stability and reliability.

During the lifecycle of a RHEL major release, bug/security fixes and feature enhancements are backported from upstream projects to RHEL packages. Sometimes these backports are done pro-actively by Red Hat to meet anticipated customer demand or to resolve important issues and vulnerabilities, sometimes these backports are done at the request of Red Hat customers. Red Hat also contribute any fixes or enhancements by Red Hat developers back to the upstream project, and will only include a contribution in Red Hat products once that contribution has been accepted by the upstream project.

Red Hat packages have a version numbering scheme based on these backported changes, usually in the form of a suffix on the upstream version number. When the upstream project increases the version number of a component, this does not necessarily mean the Red Hat package version number will follow. It is more likely that the RHEL-specific version suffix will increase instead.

For example, if a RHEL release includes package version software-2.10 of a particular piece of software, Red Hat changes will likely follow a numbering scheme like software-2.10-1 then software-2.10-2 then software-2.10-3 and so on. Even if upstream change the software to software-2.11, the RHEL package will likely remain on software-2.10-n and features/fixes from the later upstream releases may be backported into the RHEL software-2.10-n packages and the RHEL-specific version suffix will increase.

This is one of the major advantages of using the Enterprise Linux software over other distributions, as even though Red Hat software is enhanced with fixes and capabilities, software interfaces are maintained so that existing applications continue to function within a minor release, between minor releases, and even between major releases.

The exact product phases in which bugfixes, security fixes, software enhancement, and hardware enablement are performed are explained in the relevant Product Lifecycle documents.

References

Glossary

  • Major version: Released every several years - RHEL 5, RHEL 6, RHEL 7, and so on
  • Minor version: Released every 6 months or so - RHEL 6.1, RHEL 6.2, RHEL 6.3, and so on, also called a "Y release" as in "RHEL X.Y"
  • Asynchronous Errata: A package release between minor versions, also called "z-Stream" as in "RHEL X.Y.z"

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