This blog is a comparison about the support periods of RHEL and the RHEL clones like AlmaLinux, Enterprise Linux, Oracle Linux and Rocky Linux and a look back to CentOS.
CentOS Stream is a pre release of RHEL, so it can contain bugs which are fixed within RHEL and the other clones.
Overview of RHEL support cycles
Red Hat Enterprise Linux versions 5, 6, and 7 each deliver ten years of support in Full Support, Maintenance Support 1 and Maintenance Support 2 Phases followed by an Extended Life Phase. In addition, for Red Hat Enterprise Linux 5 and 6, customers may purchase annual Add-on subscriptions called Extended Life-cycle Support (ELS) to extend limited subscription services beyond the Maintenance Support 2 Phase.
With the introduction of Red Hat Enterprise Linux version 8, Red Hat is simplifying the RHEL product phases from four to three: Full Support, Maintenance Support, and Extended Life Phase.
Full Support Phase
During the Full Support Phase, qualified Critical and Important Security errata advisories (RHSAs) and Urgent and Selected High Priority Bug Fix errata advisories (RHBAs) may be released as they become available. If available, new or improved hardware enablement and select enhanced software functionality may be provided at Red Hat’s discretion.
Maintenance Support Phase
During the Maintenance Support Phases, qualified RHSAs and RHBAs may be released as they become available. Other errata advisories may be delivered as appropriate. New functionality and new hardware enablement is at the discretion of Red Hat, and varies by operating system release.
Extended Life Cycle Support (ELS)
This is offered by the Extended Life Phase (which provides access to documentation and support), during Extended Life Cycle Support (ELS) certain critical-impact security fixes, selected urgent priority bug fixes, and troubleshooting for the last minor release of a given version of Red Hat Enterprise Linux.
- On RHEL 7 ELS is not available for the architectures System z (Structure A), ARM, and POWER9.
- On RHEL 6 ELS is only available for the IBM z Systems and the x86 architecture, both 32-bit and 64-bit variants.
- On RHEL 6 a specific number of packages are supported under ELS which is listed here.
More information is available on the Red Hat Enterprise Linux website.
Most User will be use Full Support Phase and in some case Maintenance Support Phase.
AlmaLinux support cycles
AlmaLinux OS attempts to release regular updates within 1 business day from RHEL. Each release, like RHEL, comes with a 10-year lifecycle. Major releases are typically available within a few weeks to a few months following a major RHEL release.
More information is available on the AlmaLinux OS website.
AlmaLinux active support equals RHEL Full Support Phase, same end date.
AlmaLinux Security Support equals to RHEL Maintenance Support Phase, same end date.
CentOS support cycles
CentOS Linux is a rebuild of Red Hat Enterprise Linux (RHEL) source code. Major versions are supported with security and bugfix updates as long as its corresponding RHEL release is not EOL, except for CentOS Linux 8.
It was announced on December 8th, 2020 that work on CentOS Linux 8 will cease at the end of 2021 and that shift will focus to CentOS Stream.
The announcemend from December 8th 2020 that CentOS 8 will end of 2021 was the start for the AlmaLinux and Rocky Linux project. It brought many people into trouble who has done the upgrade from CentOS 7 to CentOS 8 before that announcement.
CentOS Stream support cycles
CentOS Stream is a continuously delivered Linux distribution that tracks just ahead of Red Hat Enterprise Linux (RHEL) development, positioned as a midstream between Fedora Linux and RHEL.
CentOS Stream only has major versions, and its support ends when its corresponding RHEL release leaves full support.
Everyone should decided to go the risk of an upstream or not.
EuroLinux support cycles
EuroLinux is a Polish Enterprise Linux distribution that has been in development since 2013. EuroLinux guarantees its compatibility with RHEL and CentOS. It is available in two versions: paid and free, with the paid version providing additional technical support cover.
EuroLinux releases regular updates within 1 business day from RHEL. Each release, like RHEL, comes with a 10-year lifecycle.
The table above showcases Standard Support dates. EuroLinux 6 paid Extended Support ends at July 31, 2024
More information is available on the EuroLinux website.
Interesting is that Active Support and Security Support very close to each other and that EuroLinux has the longest Active Support period within this comparsion.
Oracle Linux support cycles
Oracle Linux is an Open Source, free RHEL derivative developed by Oracle to be 100% application binary compatible alternative to Red Hat Enterprise Linux.
Available for 10 years for versions 5-9 from date of release. Includes access to patches, fixes, security patches and security alerts.
Available for 10 years for versions 5-9 from date of release. Includes access to patches, fixes, security patches and security alerts. Additionally includes live kernel patching (Certain security patches that may be applied without a reboot).
Available for a limited time, after Premier Support ends, as per agreement with Oracle. Includes patches and fixes for critical security errata and select high-impact critical bug fixes. Updates are limited to select packages listed at https://linux.oracle.com/es/packagelist.html. Also includes live kernel patching.
Differences to RHEL, problematic regulations
Unlike RHEL, Oracle Linux does not support point releases once a newer one is available. Once a new minor point release is available, the older one is immediately considered end of life and users must upgrade to continue receiving security updates. For example once 8.5 gets a general release, 8.4 is immediately end of life. Whereas on RHEL this is not the case.
Oracle Linux offers different support periods than upstream RHEL, with extra fees for using extended support which is explained here.
By default, Oracle Linux does not use the same kernel upstream RHEL uses, instead they support their own kernel builds called UEK which may not be compatible with upstream kernels. There is a Red Hat Compatible Kernel (RHCK) available as an alternative.
The minor point release topic can be an issues if the minor release is not supported by the application where the system is used for.
Rocky Linux support cyles
Rocky Linux is a Linux distribution that is intended to be a downstream, complete binary-compatible release using the Red Hat Enterprise Linux (RHEL) operating system source code. The project is led by Gregory Kurtzer, founder of the CentOS project.
Differences to RHEL, problematic regulations
Unlike RHEL, Rocky Linux does not support point releases once a newer one is available. Once a new minor point release is available, the older one is immediately considered end of life and users must upgrade to continue receiving security updates. For example once 8.5 gets a general release, 8.4 is immediately end of life. Whereas on RHEL this is not the case.
Rocky Linux doesn’t support live kernel patching, instead users who need this depend on third party paid services.
Rocky Linux doesn’t support Extended Life Cycle, resulting in a shorter support cycle compared to upstream RHEL.
With Oracle Linux and Rocky Linux we have the minor point release issue which can be problematic with the used applications on the systems, not everyone can follow these strict support / release policy.
With Rocky Linux we have also a shorter support cycle compared to RHEL.
Interesting for me are AlmaLinux and Eurolinux, AlmaLinux is following RHEL cyles and EuroLinux provides extented cycles to RHEL.
A different story is CentOS Stream, as upstream to RHEL it can contain bugs not present within the corosponding RHEL and clones.