In this guide, you will learn how to upgrade CentOS 7 to the CentOS 8.5 version. The process outlined here does not represent an official method and is not recommended for use on production environments at this time.

Step 1: Install the EPEL Repository

Begin by installing the EPEL repository using the following command:

<code># yum install epel-release -y</code>

Step 2: Install yum-utils Tools

Once EPEL has been successfully installed, proceed with installing yum-utils by running the command below:

<code># yum install yum-utils</code>

Next, install rpmconf to assist in resolving RPM packages:

<code># yum install rpmconf
# rpmconf -a</code>

Then, remove unnecessary packages using the following commands:

<code># package-cleanup --leaves
# package-cleanup --orphans</code>

Step 3: Install dnf on CentOS 7

Proceed by installing the dnf package manager, which is used by default in CentOS 8:

<code># yum install dnf</code>

Now, uninstall the yum package manager:

<code># dnf -y remove yum yum-metadata-parser
# rm -Rf /etc/yum</code>

Step 4: Upgrade CentOS 7 to CentOS 8

At this point, you're ready to perform the upgrade from CentOS 7 to CentOS 8. Start by updating your system using the new dnf package manager:

<code># dnf upgrade</code>

Now, install the required CentOS 8 release packages via dnf as shown below. This may take some time:

<code># dnf install http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/{centos-linux-repos-8-3.el8.noarch.rpm,centos-linux-release-8.5-1.2111.el8.noarch.rpm,centos-gpg-keys-8-3.el8.noarch.rpm}</code>

Note: CentOS 8 is no longer supported, and all repositories have been archived under vault.centos.org.

Upgrade the EPEL repository next:

<code>dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm</code>

After upgrading EPEL, clear any temporary files:

<code># dnf clean all</code>

Uninstall the old kernel for CentOS 7:

<code># rpm -e `rpm -q kernel`</code>

Remove any conflicting packages:

<code># rpm -e --nodeps sysvinit-tools</code>

Then begin the system upgrade to CentOS 8:

<code># dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync</code>

Note: If conflicts arise during the upgrade—for example, issues with the python36-rpmconf package—you should manually remove those problematic packages before re-running the upgrade command.

Step 5: Install the New Kernel Core for CentOS 8

Install a new kernel suitable for CentOS 8 by executing:

<code># dnf -y install kernel-core</code>

Finally, install the minimal set of packages for CentOS 8:

<code># dnf -y groupupdate "Core" "Minimal Install"</code>

You can now verify the current CentOS version with:

<code># cat /etc/redhat-release</code>

If you see output similar to above, then the upgrade from CentOS 7 to CentOS 8.5 has completed successfully.

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

Conclusion

This guide walks through the steps to upgrade from CentOS 7 to CentOS 8. We hope you found this information helpful and informative.

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