How to Upgrade CentOS 7 to CentOS 8

In this article, you will learn how to upgrade CentOS 7 to CentOS 8. The steps described herein do not depict the official upgrade and this should not be applied to a production server yet.

Step 1: Install the EPEL Repository

To start off, install the EPL repository by running:

# yum install epel-release -y
Install EPEL Repo in CentOS 7
Install EPEL Repo in CentOS 7

Step 2: Install yum-utils Tools

After successfully installing EPEL, install yum-utils by running the command below.

# yum install yum-utils
Install yum-utils in CentOS 7
Install yum-utils in CentOS 7

Thereafter, you need to resolves RPM packages by executing the command.

# yum install rpmconf
# rpmconf -a
Keep Default RPM Settings
Keep Default RPM Settings

Next, perform a clean-up of all the packages you don’t require.

# package-cleanup --leaves
# package-cleanup --orphans
Clean RPM Packages
Clean RPM Packages

Step 3: Install the dnf in CentOS 7

Now install dnf package manager which is the default package manager for CentOS 8.

# yum install dnf
Install dnf in CentOS 7
Install dnf in CentOS 7

You also need to remove the yum package manager using the command.

# dnf -y remove yum yum-metadata-parser
# rm -Rf /etc/yum
Remove Yum in CentOS 7
Remove Yum in CentOS 7

Step 4: Upgrading CentOS 7 to CentOS 8

We are now ready to upgrade CentOS 7 to CentOS 8, but before we do so, upgrade the system using the newly install dnf package manager.

# dnf upgrade
Upgrade CentOS 7
Upgrade CentOS 7

Next, install CentOS 8 release package using dnf as shown below. This will take a while.

# dnf install http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-repos-8.2-2.2004.0.1.el8.x86_64.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-release-8.2-2.2004.0.1.el8.x86_64.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-gpg-keys-8.2-2.2004.0.1.el8.noarch.rpm

Next, upgrade the EPEL repository.

dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
Upgrade EPEL Repository
Upgrade EPEL Repository

After successfully upgrading the EPEL repository, remove all the temporary files.

# dnf clean all

Remove the old kernel core for CentOS 7.

# rpm -e `rpm -q kernel`

Next, be sure to remove conflicting packages.

# rpm -e --nodeps sysvinit-tools

Thereafter, launch the CentOS 8 system upgrade as shown.

# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
CentOS 8 System Upgrade
CentOS 8 System Upgrade

Step 5: Install the New Kernel Core for CentOS 8

To install a new kernel for CentOS 8, run the command.

# dnf -y install kernel-core
Install Kernel in CentOS 8
Install Kernel in CentOS 8

Finally, install CentOS 8 minimal package.

# dnf -y groupupdate "Core" "Minimal Install"

Now you can check the version of CentOS installed by running.

# cat /etc/redhat-release
Check CentOS Version
Check CentOS Version

Read Also: How to Set Up Automatic Updates for CentOS 8

Conclusion

This article concludes on how you can upgrade from CentOS 7 to CentOS 8. We hope you found this insightful.

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131 thoughts on “How to Upgrade CentOS 7 to CentOS 8”

  1. At this step I got a fatal error:

    # dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
    

    Error:

    file /usr/lib/python3.6/site-packages/rpmconf/__pycache__/__init__.cpython-36.opt-1.pyc from install of python3-rpmconf-1.0.21-1.el8.noarch conflicts with file from package python36-rpmconf-1.0.22-1.el7.noarch

    So I just removed all the rpmconf packages:

    # rpm -evh rpmconf-1.0.22-1.el7.noarch
    # rpm -evh python36-rpmconf-1.0.22-1.el7.noarch
    # rpm -evh rpmconf-base-1.0.22-1.el7.noarch
    

    Then the upgrade action was successful, and I continued on. Maybe there is a better web page out there, but being careful in this process and backing up your data is always a good idea. The site did say not to perform on a production server.

    I then ran into errors executing this:

    # dnf -y groupupdate "Core" "Minimal Install"
    

    but when I excluded yum it at least completed:

    # dnf -y groupupdate "Core" "Minimal Install" --exclude=yum
    

    At that stage I assumed given the kernel installed well, it needs a reboot to test whether it would be successful.

    The system came back-up and I installed a program to test dnf is working. Seems like it is.

    Reply
  2. Thank you for this post. I got an error:

    sudo dnf -y –releasever=8 –allowerasing –setopt=deltarpm=false distro-sync
    [sudo] password for yjiang:
    CentOS-8 – Base 545 kB/s | 2.2 MB 00:04
    Remi’s PHP 7.2 RPM repository for Enterprise Linux 7 – x86_64 170 kB/s | 221 kB 00:01
    MySQL 8.0 Community Server 4.1 MB/s | 1.5 MB 00:00
    IUS for Enterprise Linux 7 – x86_64 1.7 MB/s | 624 kB 00:00
    MySQL Connectors Community 193 kB/s | 94 kB 00:00
    Safe Remi’s RPM repository for Enterprise Linux 7 – x86_64 615 kB/s | 2.3 MB 00:03
    CentOS-7 – SCLo sclo 496 kB/s | 1.1 MB 00:02
    geekery repository 0.0 B/s | 0 B 00:00
    CentOS-7 – SCLo rh 1.2 MB/s | 14 MB 00:11
    Extra Packages for Enterprise Linux 7 – x86_64 8.1 MB/s | 16 MB 00:02
    CentOS-8 – AppStream 1.8 MB/s | 5.8 MB 00:03
    MySQL Tools Community 505 kB/s | 553 kB 00:01
    CentOS-8 – Extras 43 kB/s | 8.1 kB 00:00
    Failed to synchronize cache for repo ‘geekery’, ignoring this repo.
    Error:
    Problem: The operation would result in removing the following protected packages: kernel

    Reply
  3. My Baremetal running centos7 started giving segmentation faulty post this. Lost all the data on the host. Please follow the procedure at your own risk.

    Reply

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