How to Upgrade from CentOS 7 to CentOS 8

This tutorial describe how to upgrade from CentOS 7.9 to CentOS 8.2.

Things to be consider while performing the upgrade from CentOS 7.9 to CentOS8.2 👇👇👇

- Always do full backup your system before upgrade
- Actual scenario might have different situation
- Make sure, all the configured repositories should be updated and able to update package for CentOS 8

- This is an unofficial, unsupported procedure !

Here are the commands for upgrade from CentOS 7.9 to CentOS 8.2 👇👇👇
# Install the EPEL Repository, if it is not configured
yum install epel-release -y

# Install yum-utils Tools
yum install yum-utils -y

# Resolves RPM packages
yum install rpmconf -y
rpmconf -a

# Perform a clean-up of all the packages which don't require
package-cleanup --leaves; package-cleanup --orphans

# Install dnf package in CentOS7
yum install dnf -y

# Remove yum package manager
dnf -y remove yum yum-metadata-parser
rm -Rf /etc/yum

# Upgrading CentOS7 using dnf
dnf upgrade -y

# Install CentOS 8 Release package (centos-linux-repos, centos-linux-release, centos-gpg-keys)

# Adjusting CentOS-Linux-BaseOS Repo to avoid any error

[baseos]
name=CentOS Linux $releasever - BaseOS
gpgcheck=1
enabled=1

# Upgrade EPEL and Remi Repository

# Removing all temporary package files
dnf clean all

# Removing old Kernel code of CentOS 7
rpm -e `rpm -q kernel`; rpm -e --nodeps sysvinit-tools

# CentOS8 system upgrade
dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync

# Install new Kernel Core for CentOS 8
dnf -y install kernel-core kernel

# Install CentOS 8 Minimum Package
dnf -y groupupdate "Core" "Minimal Install"

# Optionally, install Server with GUI with following command
# dnf -y groupupdate "Server with GUI" "Server"

# Install grub2, if does not installed
dnf install grub2 -y

# Install GRUB into MBR
lsblk

# Install GRUB in the device displayed from above command.
grub2-install /dev/sda

# Make GRUB Configuration file

# reboot the system to start the system into CentOS 8
reboot

# View the current version
cat /etc/centos-release

[Rughan]

during this upgrade dnf upgrade -y i am getting like this not able to install properly .
Extra Packages for Enterprise Linux 7 - x86_64 88 MB/s | 17 MB 00:00
Dependencies resolved.
Nothing to do. i tried to update my cento 7 to centos 8 but not working

[pranalishembalkar]

While removing old kernel ...i get error of ..cant remove protected package i.e.systemd

[JoseEduardoSalazarRamirez]

Cant install rpmconf

yum install rpmconf -y

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
No package rpmconf available.
Error: Nothing to do

[Bogy]

is there is any way to do this upgrade but offline?