Upgrading from RHEL8 to RHEL9

Install the leapp command

Note, leapp in itself isn't enough, you also need leapp-command(upgrade):

# dnf install leapp 'leapp-command(upgrade)'

Check if you can upgrade

# leapp preupgrade

It'll output a summary of problems or things to look out for regarding the upgrade. Be sure to read through it all.

I had to make the following fixes before performing the upgrade:

# sed -i s/^AllowZoneDrifting=.*/AllowZoneDrifting=no/ /etc/firewalld/firewalld.conf
# sed -i 's#PermitRootLogin yes#PermitRootLogin no#' /etc/ssh/sshd_config

Perform the actual upgrade

# leapp upgrade

Reboot the system

# reboot

Select the new GRUB option to update the initramfs

RHEL has created an upgrade specific GRUB entry. It'll generate a new initramfs, as well as upgading loads of RPM packages.

Verify that your update succeeded

[torstein@rhel9 ~]$ grep PRETTY /etc/os-release 
PRETTY_NAME="Red Hat Enterprise Linux 9.3 (Plow)"
[torstein@rhel9 ~]$ uname -r
[torstein@rhel9 ~]$

As everyone knows, though, the real test of a successful upgrade is if you get the new RHEL 9 wallpaper when logging into GNOME, so here you go: 😉


Licensed under CC BY Creative Commons License ~ ✉ torstein.k.johansen @ gmail ~ 🐘 @skybert@emacs.ch ~ 🐦 @torsteinkrause