Chapter 4. In-place Upgrades

An in-place upgrade provides a way of upgrading a system to a new major release of Red Hat Enterprise Linux by replacing the existing operating system. For a list of currently supported upgrade paths, see Supported in-place upgrade paths for Red Hat Enterprise Linux.

In-place upgrade from RHEL 6 to RHEL 7

To perform an in-place upgrade from RHEL 6 to RHEL 7, use the Preupgrade Assistant, a utility that checks the system for upgrade issues before running the actual upgrade, and that also provides additional scripts for the Red Hat Upgrade Tool. When you have solved all the problems reported by the Preupgrade Assistant, use the Red Hat Upgrade Tool to upgrade the system.
For details regarding procedures and supported scenarios, see the RHEL 7 Migration Planning Guide and the Knowledgebase solution How do I upgrade from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7?.
Note that the Preupgrade Assistant and the Red Hat Upgrade Tool are available in the RHEL 6 Extras repository.
If you are using CentOS 6 or Oracle Linux 6, you can convert your operating system to RHEL 6 using the convert2rhel utility prior to upgrading to RHEL 7. For instructions, see How to convert from CentOS or Oracle Linux to RHEL.

In-place upgrade from RHEL 7 to RHEL 8

To perform an in-place upgrade from RHEL 7 to RHEL 8, use the Leapp utility. For instructions, see the Upgrading from RHEL 7 to RHEL 8 document. Major differences between RHEL 7 and RHEL 8 are listed in Considerations in adopting RHEL 8.
Note that the Leapp utility is available in the RHEL 7 Extras repository.
If you are using CentOS 7 or Oracle Linux 7, you can convert your operating system to RHEL 7 using the convert2rhel utility prior to upgrading to RHEL 8. For instructions, see How to convert from CentOS or Oracle Linux to RHEL.