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In this article, you will learn how to upgrade CentOS 7 to CentOS 8.5 release. The steps described herein do not depict the official upgrade and this should not be applied to a production server yet.
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Step 1: Install the EPEL Repository
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To start off, install the EPL repository by running:
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# yum install epel-release -yrn
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Step 2: Install yum-utils Tools
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After successfully installing EPEL, install yum-utils by running the command below.
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# yum install yum-utilsrn
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Thereafter, you need to resolve RPM packages by executing the command.
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# yum install rpmconfrn# rpmconf -arn
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Next, perform a clean-up of all the packages you don’t require.
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# package-cleanup --leavesrn# package-cleanup --orphansrn
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Step 3: Install the dnf in CentOS 7
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Now install the dnf package manager which is the default package manager for CentOS 8.
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# yum install dnfrn
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You also need to remove the yum package manager using the command.
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# dnf -y remove yum yum-metadata-parserrn# rm -Rf /etc/yumrn
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Step 4: Upgrading CentOS 7 to CentOS 8
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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.
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# dnf upgradern
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Next, install CentOS 8 release package using dnf as shown below. This will take a while.
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# 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}rn
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Note: CentOS 8 is dead and all the repos have been moved to vault.centos.org.
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Next, upgrade the EPEL repository.
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dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpmrn
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After successfully upgrading the EPEL repository, remove all the temporary files.
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# dnf clean allrn
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Remove the old kernel core for CentOS 7.
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# rpm -e `rpm -q kernel`rn
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Next, be sure to remove conflicting packages.
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# rpm -e --nodeps sysvinit-toolsrn
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Thereafter, launch the CentOS 8 system upgrade as shown.
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# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-syncrn
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Note: If you get errors about conflicting packages, for example in my case there were conflicts about the existing python36-rpmconf package. I removed this package, similarly if you get any conflicts just remove those packages and try running the above upgrade command.
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Step 5: Install the New Kernel Core for CentOS 8
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To install a new kernel for CentOS 8, run the command.
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# dnf -y install kernel-corern
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Finally, install CentOS 8 minimal package.
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# dnf -y groupupdate "Core" "Minimal Install"rn
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Now you can check the version of CentOS installed by running.
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# cat /etc/redhat-releasern
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If you see the above output, I have successfully upgraded from CentOS 7 to CentOS 8.5 release.
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Read Also: How to Set Up Automatic Updates for CentOS 8
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Conclusion
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This article concludes on how you can upgrade from CentOS 7 to CentOS 8. We hope you found this insightful.
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