How to Upgrade your Servers from Rocky Linux 8 to 9

In this tutorial, you will learn how to upgrade your servers from Rocky Linux 8 to 9.

What is Rocky Linux?:

Rocky Linux is a Linux distribution developed by Rocky Enterprise Software Foundation. It is intended to be a downstream, complete binary-compatible release using the Red Hat Enterprise Linux (RHEL) operating system source code. The project's aim is to provide a community-supported, production-grade enterprise operating system. Rocky Linux, along with Red Hat Enterprise Linux and SUSE Linux Enterprise, has become popular for enterprise operating system use.

Rocky Linux 9.0, the latest version of the open source enterprise operating system designed to be fully bug-for-bug compatible with Red Hat Enterprise Linux (RHEL), is now generally available. The update includes new security and networking features, and a new open source build system called Peridot.

Released on 14 July 2022, Rocky Linux 9.0 has all of the build chain infrastructure tools for developers to pick up Rocky Linux or extend or reproduce the Operating system, should a developer want to do something independently of the community or any upstream supporting organization. A primary goal behind developing the new, cloud-native build system was assuring that new versions of Rocky can be released within one week of new RHEL version releases.

What's New in Rocky Linux 9?:

Some of the new features of Rocky Linux 9 are:

Rocky Linux 9 will be supported until May 31st, 2032
Ships with GNOME 40 as the default desktop environment
XFS now supports Direct Access (DAX) operations
NFS introduces the “eager write” mount option to help reduce latency
Rocky Linux 9 has many of the latest runtimes and compilers, including GCC 11.2.1, LLVM (13.0.1), Rust (1.58.1), and Go (1.17.1)
Python 3.9 will be supported for the entire lifecycle of Rocky Linux 9 and comes with many new features
Node.js 16 include an upgrade to the V8 engine to version 9.2
Ruby 3.0.3 provides several performance improvements, along with bug and security fixes
Perl 5.32 provides bug fixes and enhancements, including Unicode version 13
PHP 8.0 provides bug fixes and enhancements, including the use of structured metadata syntax
Root user authentication with a password over SSH has been disabled by default
OpenSSL 3.0 adds a provider concept, a new versioning scheme, and improved HTTPS
The Cockpit web console has an improved performance metrics page that helps identify causes of high CPU, memory, disk, and network resource usage spikes.

Recommended Book: How Linux Works, 3rd Edition: What Every Superuser Should Know by Brian Ward (Author)
Recommended Online Training: Linux Command Line for Beginners

System Requirements:

With Rocky Linux 9.0, some older CPUs will not work well, or perhaps at all. The following architectures are considered minimum requirements for a successful install:

AMD and Intel 64-bit architectures (x86-64-v2)
The 64-bit ARM architecture (ARMv8.0-A)
IBM Power Systems, Little Endian (POWER9)
64-bit IBM Z (z14)

Environment Specification:

We are using a minimal Rocky Linux 8 virtual machine with following specifications.

CPU - 3.4 Ghz (2 cores)
Memory - 2 GB
Storage - 20 GB
Operating System - Rocky Linux 8.6 (Green Obsidian)
Hostname – rockylinux-01.centlinux.com
IP Address - 192.168.116.128 /24

Updating Software Packages:

By using a ssh client, connect with rockylinux-01.centlinux.com as root user.

Rebuild cache of enabled yum repositories.

# dnf makecache

Execute following dnf command to update software packages in your Rocky Linux server.

# dnf update -y

Gathering System Information:

Here, you are going to upgrade your server operating system from Rocky Linux 8 to 9.

Therefore, it is good to note down the information about your existing system components before starting upgrade process.

Check versions of Linux operating system, Linux Kernel and other installed applications as follows.

# cat /etc/rocky-release
Rocky Linux release 8.6 (Green Obsidian)

# uname -r
4.18.0-372.16.1.el8_6.0.1.x86_64

# mysql -V
mysql  Ver 15.1 Distrib 10.3.32-MariaDB, for Linux (x86_64) using readline 5.1

# httpd -v
Server version: Apache/2.4.37 (rocky)
Server built:   Jun 22 2022 14:17:54

# php -v
PHP 7.2.24 (cli) (built: Oct 22 2019 08:28:36) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies

Upgrading Yum Repositories from Rocky Linux 8 to 9:

For upgrading your yum repositories from Rocky Linux 8 to 9, you have to upgrade following three software packages.

rocky-gpg-keys
rocky-release
rocky-repos

You can either download above software packages from Rocky Linux website.

Or you can execute following dnf command to install all three of them on your Linux operating system.

# dnf install -y https://download.rockylinux.org/pub/rocky/9/BaseOS/x86_64/os/Packages/r/{rocky-gpg-keys-9.0-2.2.el9.noarch.rpm,rocky-release-9.0-2.2.el9.noarch.rpm,rocky-repos-9.0-2.2.el9.noarch.rpm}

You can safely ignore the warning during the execution of above command.

Upgrading Rocky Linux 8 to 9:

Now you can easily upgrade your Linux operating system by executing following command at Linux Bash prompt.

# dnf -y --releasever=9 --allowerasing --setopt=deltarpm=false distro-sync

Above command takes a couple of minutes to complete and successfully upgrades your server operating system from Rocky Linux 8 to 9. It also upgrade software applications and Linux Kernel as well.

In Rocky Linux 9, the RPM backend database format has been changed from Berkley Database Backend to SQLite.

Therefore, you need to rebuild your RPM database once to upgrade it to SQLite backend.

# rpm --rebuilddb
warning: Converting database from bdb_ro to sqlite backend

Reboot your Linux operating system with the new Linux kernel.

# reboot

Verify Software Versions after Upgrade:

During system boot, you may observe the Old Linux Kernel 4.18 is still listed in the GRUB boot menu.

It is the default behavior of Linux operating system to keep two previous Kernels for fallback support.

Although if you don't like it there, you can remove it by following our guide on how to remove old Linux kernels.

Check versions of Linux operating system, Linux Kernel and installed applications as follows.

# cat /etc/rocky-release
Rocky Linux release 9.0 (Blue Onyx)

# uname -r
5.14.0-70.17.1.el9_0.x86_64

# mysql -V
mysql  Ver 15.1 Distrib 10.5.13-MariaDB, for Linux (x86_64) using  EditLine wrapper

# httpd -v
Server version: Apache/2.4.51 (Rocky Linux)
Server built:   Mar 21 2022 00:00:00

# php -v
PHP 8.0.13 (cli) (built: Nov 16 2021 18:07:21) ( NTS gcc x86_64 )
Copyright (c) The PHP Group
Zend Engine v4.0.13, Copyright (c) Zend Technologies
    with Zend OPcache v8.0.13, Copyright (c), by Zend Technologies

You can see that your Linux operating system alongwith Linux Kernel and installed applications has been upgraded from Rocky Linux 8 to 9.

Conclusion:

In this tutorial, you have learned how to upgrade your servers from Rocky Linux 8 to 9.