What's the difference between a major, minor, and asynchronous release?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux
  • Red Hat Enterprise Virtualization
  • Red Hat Storage Server

Issue

  • How do I distinguish between a major release, a minor release, and an asynchronous release?
  • How do I identify the release I'm running?

Resolution

Compare and Contrast

Major Release Minor Release Asynchronous Erratum
Examples (Naming) Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 9.1 RHSA-2023:xxxx-x
Requirements None Major Release Major or Minor Release
Release: Frequency Years Months Days/Weeks
Release: Basis/Driver Schedule Schedule Incident
Includes: Number of Updated Packages All (thousands) Some (hundreds) Few
Includes: Rebases1 All (thousands) Few None
Includes: Select Backporting Yes Yes Yes
Includes: Features, Hardware Enablement Yes Yes2 No
Includes: Critical and urgent security and bug fixes Yes Yes Yes
Includes: Criteria Liberal Strict2 Very Strict3
Hardware Certification Required Yes No4 No
Available to all customers Yes Yes Yes
Fully Tested by Red Hat QA Yes Yes Yes
Utilizes Red Hat Network Yes Yes Yes
Application compatibility Assurances No5 Yes Yes
Is Upgradable Yes Yes Yes

Please refer to the Red Hat Enterprise Linux Life Cycle Page for more information.

Identifying a Release

Major Release

One of the easiest ways to identify the major release is to check the kernel version, or to check the /etc/redhat-release file for the major version. In the following example we can see that the system's kernel version indicates it is a RHEL 7 system based on the 'el7'. In the /etc/redhat-release file we see that the system is described as "7.7" with the first 7 being the major release, and the second being the minor release:

[root@7 ~]# uname -a
Linux 7.6 3.10.0-1062.1.1.el7.x86_64 #1 SMP Tue Aug 13 18:39:59 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
[root@7 ~]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.7 (Maipo)

Installation of packages between major releases is not supported, and therefore a system is based on a major release until upgrading/migrating to the next major release is required.

  • For example, a system may be based on Red Hat Enterprise Linux 5, or Red Hat Enterprise Linux 6, but not a mix of both.

Minor Release

Installed on top of major releases to provide larger-scale point-release updates via Red Hat Subscription Manager, after initial installation via traditional methods (PXE, DVD, etc.). More difficult to identify since the installation of packages between minor releases is supported. Red Hat does not require a system to be entirely composed of packages from a single minor release, but many regard the kernel version and the contents of /etc/redhat-release as two data points that assist in labeling a minor release without deeper introspection into additional userspace package updates. Others have stated that minor releases are just hundreds of errata published on the same day and labeled as a release for convenience.

  • For example, a system may have the kernel installed from Red Hat Enterprise Linux 8.1, but user space packages installed from Red Hat Enterprise Linux 8.2. This would still be considered fully supported.

  • Referring back to the example from "Major Release", it should be noted that this system has a kernel from "7.6", while the /etc/redhat-release file states that the system is RHEL 7.7. Because minor releases are comprised of updates to many packages, it is not always possible to tell what release all of the packages are from. Different environments may have different requirements, so knowing ahead of time and ensuring that version locks are in place when required can assist with ensuring that only packages from a specific minor release get installed.

[root@7 ~]# uname -a
Linux 7.6 3.10.0-1062.1.1.el7.x86_64 #1 SMP Tue Aug 13 18:39:59 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
[root@7 ~]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.7 (Maipo)

IMPORTANT: Red Hat's independent software vendors (ISVs) may require that a system have packages installed solely from a single minor release for it to be fully supported by the software vendor. Please check with the ISV if there are any support caveats to installing packages from different minor releases on a single system.

Asynchronous Release

Easily identified via installed RPMs mapped to specific errata, and can be queried via yum and rpm commands.

Footnotes

  1. "Rebases" refers to user space package rebases, as well as kernel device driver rebases ↩︎

  2. Highly dependent on where the release is in its product life cycle. ↩︎ ↩︎

  3. Each product has its own published criteria for asynchronous errata. ↩︎

  4. Not required if already certified during the major release. For example, if certified on Red Hat Enterprise Linux 8.2, it is certified on all newer minor releases as well, but not 8.1 or 8.0. ↩︎

  5. No ISV assurances due to a full rebase of the product/distribution. Please refer to the ISV directly or the Red Hat ISV Software Catalog for a list of certified software solutions on Red Hat products. ↩︎

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