How to convert from CentOS Linux 8 to CentOS Stream 8

CentOS Linux 8 was discontinued at the end of 2021. Check out more information about that in this in this article CentOS Linux 8 will end in 2021 and shifts focus to CentOS Stream.

The team at CentOS decided to shift focus to CentOS stream, an upstream version of RHEL. CentOS stream places itself between Fedora Linux and RHEL. It is not 100% RHEL clone but ahead of RHEL development. Other distros that are 100% compatible with RHEL 8 have come up including Rocky Linux and Alma Linux.

In this guide, we will learn how to convert an existing CentOS 8 distro into Centos 8 Stream without reinstalling a new operating system.

Table of Content

Ensure your system is up to date
Backup your CentOS Linux system
Install CentOS Stream package

1. Ensure your system is up to date

Ensure that the server is updated using this command:

sudo dnf update -y

Let us also verify CentOS Linux 8 version using this command:

$ cat /etc/os-release
NAME="CentOS Linux"
VERSION="8"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Linux 8"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-8"
CENTOS_MANTISBT_PROJECT_VERSION="8"

2. Backup your CentOS 8 system

It is a good practice to ensure periodic updates on your system. If you have application data in the system ensure that it is backed up. Please also make OS snapshot to revert back when something goes wrong. Always keep verified backups.

3. Install CentOS Stream Package

Use this command to install the CentOS-Stream package:

sudo dnf install -y centos-release-stream

4. Convert the system from CentOS 8 to CentOS Stream

After installing the required package, we can start migrating from CentOS 8 to CentOS Stream. First, we must swap repos. This command will remove the CentOS 8 repos and replace it with the CentOS Stream repos. We will get all updates and libs/apps from CentOS Stream.

sudo dnf swap centos-linux-repos centos-stream-repos

List the repos with this command:

sudo dnf repolist

Output:

$ sudo dnf repolist
repo id                                                                                                repo name
appstream                                                                                              CentOS Stream 8 - AppStream
baseos                                                                                                 CentOS Stream 8 - BaseOS
extras                                                                                                 CentOS Stream 8 - Extras

Next, we need to get packages for CentOS Stream ABI/API. This will upgrade or downgrade packages to match the new ABI/API and break 100% RHEL compatibility due to ABI/API change. Use this command to achieve that:

sudo dnf distro-sync

5. Reboot the system

We need to reboot the system to ensure that the changes have been applied. Use this command to reboot the system:

sudo systemctl reboot

6. Verifying the migration

Once the reboot is done, login to the server and confirm that it was successful. Verify the version to make sure we are now switched to Centos 8 Stream using this command:

$ cat /etc/os-release
NAME="CentOS Stream"
VERSION="8"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Stream 8"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://centos.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux 8"
REDHAT_SUPPORT_PRODUCT_VERSION="CentOS Stream"

We can also check the CentOS release file

$ cat /etc/centos-release
CentOS Stream release 8

Checking the hostname with hostnamectl will also reveal the info

$ cat /etc/centos-release
CentOS Stream release 8
[centos@dev-ce8-1-srv ~]$ hostnamectl
   Static hostname: dev-ce8-1-srv.citizix.com
         Icon name: computer-vm
           Chassis: vm
        Machine ID: 4d78db4a684b6f64404255df88b2c437
           Boot ID: 2f9319edf2ed4c7a9b32f397ed338c32
    Virtualization: kvm
  Operating System: CentOS Stream 8
       CPE OS Name: cpe:/o:centos:centos:8
            Kernel: Linux 4.18.0-358.el8.x86_64
      Architecture: x86-64