How to upgrade CentOS from 7 to 8




The new version of CentOS 8 offers the latest technologies, packages, and services and will continue to be supported until 2029. There is no official way to upgrade from CentOS 7 to CentOS 8, but unofficially it can be done. Production servers should not use such a procedure. Take a snapshot of your VPS before upgrading, so that you can restore it if necessary. So let’s start the upgrading process.








Step 1: Cleaning Up your current system





You should clean up your current system before you install CentOS 8 in order to avoid leftovers, unneeded packages, or conflicts.



First, ensure your system is up to date. Run the following command:


# yum update -y 



Install epel-release repository:


# yum install -y epel-release


Install the yum-utils and rpmconf packages:



# yum install -y yum-utils rpmconf


We’ll use rpmconf now that it has been installed to resolve our rpm packages:



# rpmconf -a



Lastly, ensure that any orphaned or unneeded packages have been removed:




package-cleanup --leaves
package-cleanup --orphans







Step 2: Replacing Packages






The next step involves replacing the important package and repository repositories with their CentOS 8 equivalents.  




Install the DNF package manager, which uses rpm packages:




# yum install -y dnf



Remove the yum package manager:



dnf -y remove yum yum-metadata-parser
rm -Rf /etc/yum


You should then run a DNF system update:



# dnf upgrade -y



Next, install the CentOS 8 packages:




# dnf install{centos-release-8.1-1.1911.0.8.el8.x86_64.rpm,centos-gpg-keys-8.1-1.1911.0.8.el8.noarch.rpm,centos-repos-8.1-1.1911.0.8.el8.x86_64.rpm}



And upgrade the EPEL repository:



# dnf -y upgrade



As a last step, delete all temporary files:



# dnf clean all






Step 3: Install the New Kernel and Release







Installation of the new Linux kernel and the new CentOS 8 release is the last step in switching over to CentOS 8.




First, remove the old kernel:



# rpm -e `rpm -q kernel`



If there are any conflicting packages, remove them:



# rpm -e --nodeps sysvinit-tools



Upgrade CentOS 8:



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




To install the new kernel core, follow the command:



# dnf -y install kernel-core



After that, Run the CentOS 8 Minimal install:



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







Based on the os-release and redhat-release files, you can verify your CentOS version. Thanks for reading! I hope it was informative for you! 







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