Upgrade RHEL6 to RHEL7

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For upgrading we need to first run pre-upgrade check. After that we can upgrade using redhat-upgrade-tool. Overall upgrade from RHEL 6 to RHEL 7 can be done as follows:

1. Running preupgrade check via:
   1. Clear the version lock

      yum versionlock clear

   2. Enable the Extras repository

      subscription-manager repos --enable rhel-6-server-extras-rpms --enable rhel-6-server-optional-rpms

   3. Install the Preupgrade Assistant and Red Hat Upgrade Tool

      yum install preupgrade-assistant preupgrade-assistant-el6toel7 redhat-upgrade-tool

   4. Update all packages to their latest RHEL 6 version

      yum update
      shutdown -r now

   5. Run the Preupgrade Assistant to perform an assessment of the system

      preupg

      This should generate an HTML file for us to view.

      There are options for preupg such as --cleanup for cleaning up after previos run; -S or --skip-common to skip common tests and -d for debug. Apart from HTML it also generate a log file which mostly has same information as what is displayed on screen.

   6. Resolve problems found by the Preupgrade Assistant during the assessment by following the Remediation text in the report. ##: Sometimes for KDE and Gnome the text will include list of packages that need to be removed. We should remove them using yum for preupg test to succeed.
   7. Run the Preupgrade Assistant again. If there are no new problems to be resolved, you can proceed with upgrading your system
2. Upgrade
   1. Install the yum-utils package

      yum install yum-utils redhat-upgrade-tool

   2. Disable active repositories:

      yum-config-manager --disable \*

   3. Download latest RHEL 7 ISO
      1. Visit the Red Hat Customer Service Portal at https://access.redhat.com/login and enter your user name and password to log in.
      2. Click Downloads to visit the Software & Download Center.
      3. In the Red Hat Enterprise Linux area, click Download Software to download the latest version of the software.
      4. Copy the RHEL 7.9 iso to /root directory
   4. Start the upgrade

      redhat-upgrade-tool --iso iso_path --cleanup-post

      For example

      redhat-upgrade-tool --iso /root/rhel-server-7.9-x86_64-dvd.iso --cleanup-post

   5. Reboot the system when prompted

      shutdown -r now

3. (Optionally) Update your new RHEL 7 packages to their latest version

   yum update

4. Verify that the system was upgraded to the desired minor version of RHEL 7

   cat /etc/*release

5. (Optionally) Install the gnome desktop

   yum groupinstall 'X Window System' 'GNOME'

6. (Optionally) Enable and start the graphical environment

   systemctl set-default graphical.target
   systemctl start graphical.target

Refer:

• https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.4/html/installation_guide/rhel6_to_rhel7

Home > RHEL > Upgrade RHEL6 to RHEL7