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.
Note that the Preupgrade Assistant
and the Red Hat Upgrade Tool
are available in the RHEL 6 Extras repository
In-place upgrade from RHEL 7 to RHEL 8