Does Red Hat support upgrades between major versions of Red Hat Enterprise Linux?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 4
  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Issue

  • How to upgrade from one version of the Red Hat Enterprise Linux OS to another?
  • Can I migrate between major versions of Red Hat Enterprise Linux?
  • Does Red Hat support an update between major versions of Red Hat Enterprise Linux (eg, 5 to 6)?
  • Can I install Red Hat Enterprise Linux 6 on a Red Hat Enterprise Linux 5 system?
  • Installation media does not include an upgrade option
  • How to upgrade from RHEL 5 to RHEL 6 ?

Resolution

Red Hat Enterprise Linux 4, 5, 6

  • Red Hat does not support in-place upgrades between major versions 4, 5 and 6 of Red Hat Enterprise Linux. (A major version is denoted by a whole number version change. For example, Red Hat Enterprise Linux 5 and Red Hat Enterprise Linux 6 are both major versions of Red Hat Enterprise Linux).

  • In-place upgrades across major releases do not preserve all system settings, services or custom configurations. Consequently, Red Hat strongly recommends fresh installations when upgrading from one major version to another. After a fresh installation alongside an existing server installed with Red Hat Enterprise Linux , you can migrate your settings, software and data to the new server in order to ensure they are all successful and all of your software runs as expected. This also helps to ensure that your data is safely transported from backup to the new system for your fresh start.

    • Having said this, there is an upgrade option that can be used at your own risk to allow an upgrade without requiring a full reinstall. To get this functionality, insert the installation CD of the new version and enter the following command at the boot prompt:
# linux upgradeany

This will walk you through the upgrade procedure, which very closely resembles a normal installation. Again, the process noted above is not supported by Red Hat and should not be used in production environments. After this upgrade procedure, should you call into Red Hat for support, Red Hat will support the resulting system as if it were a clean installation only. Any issues not related to the upgrade will be supported. If at any time a problem appears to be the result of an in-place upgrade procedure, Red Hat may require you to reinstall the system.

Comment

  • Red Hat recommends that you do a complete backup of your system before you attempt the upgrade.
  • If there were any third party packages involved in the previous installation, re-install them.
  • Individual package configuration files may or may not work after  performing an upgrade due to changes in various configuration file  formats or layouts.
  • If any of Red Hat's layered products (such as  the Cluster Suite) were installed, it may need to be manually upgraded  after the OS upgrade has been completed. Some layered products, like CloudForms, do not support the underlying OS to be upgraded due to the significant changes between RHEL6 and RHEL7 packages (like databases) upon which the layered product relies.
  • The upgrade option is known to cause erratic system behavior in some cases.
  • In cases where unexpected results occur, Red Hat Global Support Services  may have no choice but to walk you through a reinstallation and  recommended migrations.

As per document link, Red Hat Enterprise Linux 6 Installation Guide, Chapter 37. Upgrading Your Current System

Once upgraded or re-installed, re-register system as described at    How do I re-register my system with Red Hat Network (RHN) Classic ?

Red Hat Enterprise Linux 7

Red Hat currently supports only upgrades from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7 for specific/targeted use cases only. More information can be found at the following links:

Red Hat Enterprise Linux 8

Please feel free to file a support case with Red Hat Global Support Services or via a comment in the Discussions area of the Customer Portal.

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.

11 Comments

It would have been helpful to provide a link to what procedure IS recommended if you're trying to update/upgrade across major revisions.  How are the entitlements handled?  Should I delete the machine from the RHN and add it again later?  What?

Hello,
There is no supported upgrade path between major versions of Red Hat Enterprise Linux. This procedure outlines a possible path. But the resulting system, may have problems that Red Hat would be unable to resolve without a full install. The system would need to be deleted from RHN and re-registered after the upgrade.

For RHEL6, using the 'linux upgradeany' option, gives you the option to keep the existing installaion and upgrade it.

Any recommendations, best practices regarding how to "migrate your settings, software and data" ?

Charles, I'm not aware of any personally but this would be a great topic to bring up on the RHEL support community here on the Portal: https://access.redhat.com/groups/red-hat-enterprise-linux

Our users there will definitely be able to offer some advice.

The old adage of ...there is always time to do it over, there is never time to do it right.... is well applied to major version upgrades.

If it is important for it to work right, do a fresh reinstall. Otherwise you will be sorry.

RedHat, Solaris, HPUX, and a few others have always recommended against upgrades between major versions. For good reason.

I can tell you war stories including what should have been a painful 3 month 3000 man/hour Documentum upgrade (3 major versions up) with an easy backout plan, and turned into a 14 month uber painful massive effort with a career ending backout plan using over 12,000 man/hours.
All because the CIO declared no new Sun Hardware, and my manager decided he did not want ANY more Sun hardware, not even $60k worth of new hardware. So we had to do an in place upgrade instead of a fresh install then switch over.

Hello Team,
We are planing to migrate all production RHEL 4 servers to REEL 6.x (Latest)
1. Migrate 4.x to 6.x will possible?
2. Migrate 4.x to 5.x and 5.x to 6.x?
3. Rebuilt OS for 6.x

Monica, currently the only supported upgrade method is planned for RHEL 6.5 and later to 7.0 and later, and this is for only limited use cases.

What are the supported use cases for upgrading RHEL 6 to RHEL 7?
https://access.redhat.com/site/solutions/799813

I would recommend a fresh install for all the cases you mention above.

All,

Do not even try this scenario. A fresh install is the only save way to go.
Third party packages e.g switches from Openoffice to Libreoffice to name an obvious switch is an example where the update may fail.

To remove all failed upgrades that "make a landfill of your rpm database" will be hard to cleanup.

I cannot backup this with real life experience on RHEL, but in the old days on Red Hat 7 updating to RHEL 9 it was already a mess to cleanup the rpm database.

Be aware, if Red Hat support finds out you did an inplace upgrade, reinstall is the key word they will use. So why not do it in the first place.

It may also be a good idea to do a fresh replacement of your application/database so "remembering" kernel settings is less import for the new database most certainly demands other settings.

Kind regards,

Jan Gerrit Kootstra

I was looking for information on how to upgrade RHEL5 to RHEL6, not RHEL6 to RHEL7. Please make a new document for upgrading RHEL6 to RHEL7 and put back any pertinent information for upgrading RHEL5 to RHEL6 in this document.
According to the article on your website entitled, "Red Hat Enterprise Linux Life Cycle", Phase 3 support for RHEL5 does not end until the end of this month (March 31, 2017); therefore, I feel only providing support for RHEL6 to RHEL7 is a little premature, especially since you offer Extended Life-cycle Support until November 30, 2020 for RHEL5.
Bill Duff mentioned back in March of 2011 (5 years ago) that this article could use a link to the procedure or instructions to use when upgrading RHEL5 to RHEL6; however, I see this information was not added as requested. Even if I do a new install of RHEL6 on a new server, I need to know how to "migrate" or port information from my RHEL5 server to my RHEL6 server. I also need to know if I need to start with a lower minor release in RHEL6 and then upgrade to a higher release after migrating my RHEL5 configuration.

Thank you for writing, Jana. Quickly looking back through some of this document's edit history, I do not see where any information about upgrading RHEL5 to 6 was removed. Red Hat's stance on doing such an upgrade remains the same as it always has: we do not support in-place upgrades, and strongly recommend fresh installations when moving from one major version to another. (RHEL6 to 7 is supported in only specific/targeted use cases.)

There seems to be some confusion as to the meaning behind the RHEL lifecycle phases. RHEL5 is currently in Production Phase 3 -- which means it only gets "Critical impact Security Advisories (RHSAs) and selected Urgent Priority Bug Fix Advisories (RHBAs)". Adding the brand-new feature of being able to perform an in-place upgrade is out-of-scope for this phase. Additionally, no new features are given during the Extended Life-cycle Support phase, either.

You express some concern over installing a new RHEL6 operating system on a server and what RHEL5 configuration & data would need migrated to it. Every server is different, depending on what a customer uses it for. (Is it used as an Apache web server? A BIND server? Are user accounts local, or do users authenticate against LDAP or Active Directory? Etc., etc.) It would not be possible to cover all the possible configurations in a document like this. We encourage you to open a support case with specific questions about the RHEL5 data and configurations you wish to carry over to a new RHEL6 install.

Please also be warned that configurations should not be copied, verbatim, from RHEL5 to 6 (or 7) without a thorough examination of them. A package in RHEL6 may be significantly newer than what was provided in RHEL5; configuration options may have been depreciated between the two versions.

Finally, you should not need to start at a low RHEL6 minor version. All RHEL major versions maintain compatibility among their minor versions.