Upgrading RHEL 7 to 8 With Leapp

Overview

The Leapp utility is a framework for updating and upgrading operating systems as well as applications. The operations of this utility consist of two phases 1. the preupgrade Phase – that chack the upgrade possibilities and 2. the actual upgrade phase – that map packages between previous and current versions of the software packages.

Verifying the system before the Upgrade:

# head -1 /etc/*rel*
# uname -r
# sudo grubby --default-kernel

Step 1: Preparing for the Upgrade

01. If you are upgrading a remote system, ensure remote connection through a console such as VNC.
02. Ensure the system backup to avoid any kind of loss such as data, application, configuration, etc.
03. Shut down all production services such as application, database, corn jobs, etc.
04. Disable Secure Boot if it is running.

To check the status of Secure Boot, choose one of the following commands:
Using bootctl status,

# sudo bootctl status

Or using mokutil –sb-state,

# sudo mokutil --sb-state

If Secure Boot is enabled on your system go to the firmware/bios at boot time and disable the option.

05. Verify that the locale is set to en_US.UTF-8.

# cat /etc/locale.conf

If necessary, edit the file to set the locale accordingly.

# sudo localectl set-locale LANG=en_US.UTF-8

06. If your system has network-mounted file systems, unmount them and comment out related entries in the /etc/fstab file.

07. Ensure your system has been successfully registered to the Red Hat Content Delivery Network (CDN) using the Red Hat Subscription Manager.

# sudo subscription-manager list --installed

If your system is not registered to the Red Hat Content Delivery Network (CDN) run the following command and check the status:

# sudo subscription-manager register --username MyRedHatUser --password SuperSecretPassword --auto-attach

08. And enable the Base and Extras repository where Leapp and its dependencies are available:

# sudo subscription-manager repos --enable rhel-7-server-rpms --enable rhel-7-server-extras-rpms

Then check the Available Enable Repositories:

# sudo subscription-manager repos --list-enabled

09. Unset the Subscription Manager release and clear the version lock:

# sudo subscription-manager release --unset
# sudo yum version lock clear

08. Obtain the latest Oracle Linux 7 packages.

# sudo yum update

10. Reboot the system.

# sudo reboot

11. Install the Leapp utility while enabling certain repositories, as follows:

# sudo yum install leapp-upgrade

Ensure your system does not use more than one Network Interface Card (NIC) with a name based on the prefix used by the kernel (eth). For instructions on how to migrate to another naming scheme before an in-place upgrade to RHEL 8, see How to perform an in-place upgrade to RHEL 8 when using kernel NIC names on RHEL 7.

12. Temporarily disable antivirus software to prevent the upgrade from failing.

Step 2: Upgrading the System

01. Grant root SSH login permissions in the /etc/ssh/sshd_config file.

# PermitRootLogin yes

02. Run the pre-upgrade command.

# sudo leapp preupgrade

This process assesses upgradability, pre-upgrade report, and an answerfile file.

Analyzing the Leapp Report

The /var/log/leapp/leapp-report.txt file summarises the issues, identifies potential risks and also suggests the remediations path to the upgrade. The risks are classified as an inhibitor, high, medium, or low. The inhibitor and high risk would prevent an upgrade. Check out this link for remediations the issues.

Providing Information to the Leapp Answerfile

Use the leapp answer command to provide the answer to the answerfile.

# sudo leapp answer --section remove_pam_pkcs11_module_check.confirm=True

Or edit the contents of /var/log/leapp/answerfile.

confirm = True

If your system uses the Btrfs file system you must use the following command.

# sudo leapp answer --section confirm_UEK_install_and_default_boot_kernel.confirm=True

Performing the Upgrade

On a physical system:

# sudo leapp upgrade

Reboot the system after completing the upgrade process.

# sudo reboot

Monitor the boot progress on the console, while the system is rebooting.

Verifying the system after Upgrade

# head -1 /etc/*rel*
# uname -r
# sudo grubby --default-kernel

Step 3: Completing Postupgrade Tasks

Check this link.

Conclusion

This tutorial helps you How to upgrade your existing Oracle Linux 7 system to 8. If have any queries please comment to us. follow the link to Upgrading Red Hat Linux 7 to 8 With Leapp.

References

In this tutorial, I follow the official docs as reference Performing Systems Upgrade With Leapp (RHEL 8).