How To :- Upgrade or Update CentOS 7 to CentOS 8 to Latest Version

In this article I will explain how to upgrade 7 old CentOS version to latest version CentOS 8.

Upgrade or Update CentOS 7 to CentOS 8

Step #1 : Install EPEL Repository

# yum install epel-release -y

Step #2 : Install yum-utils Tools

# yum install yum-utils

Once above package installed now need to resolve RPM packages using below command.

# yum install rpmconf

# rpmconf -a

Let’s clean all unnecessary package which are not required.

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

Step #3 : Install dnf package on CentOS 7

# yum install dnf

Now remove the yum package manage using below command.

# dnf -y remove yum yum-metadata-parsar
# rm -Rf /etc/yum

Step #4 : Upgrade CentOS 7 to CentOS 8

All required dependencies are completed let’s upgrade CentOS 7 to CentOS 8 using dnf package manager.

# dnf upgrade

Next, Will need to install CentOS 8 release package using dnf command. Note this step will take some time.

# dnf install http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/{centos-linux-repos-8-2.el8.noarch.rpm,centos-linux-release-8.4-1.2105.el8.noarch.rpm,centos-gpg-keys-8-2.el8.noarch.rpm}

Upgrade EPEL repository now.

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

Once successfully completed above command now let’s remove the all temporary files.

# dnf clean all

Let’s remove old  CentOS 7 kernel.

# rpm -e 'rpm -q kernel'

Make sure conflicted package should be removed.

# rpm -e --nodeps sysvinit-tools

Let’s start upgrading CentOS 8 like below:

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

Step #5 : Install CentOS 8 Kernel

Run the below command to install CentOS 8 kernel as shown below:

# dnf -y install kernel-core

Now install Minimal Package for CentOS 8

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

Next, check the version of newly installed CentOS 8 suing below command.

# cat /etc/redhat-release

Output:

# cat /etc/redhat-release
CentOS Linux release 8.0.1905 (Core)

Congratulation!! You successfully upgraded your CentOS 7 to CentOS 8.

Steps to Update or Upgrade CentOS minor Version

All CentOS 7.0, 7.1 and 7.2 users can upgrade their system to the latest version CentOS 7.3.

You can use the “update” option to upgrade all your CentOS system software to the latest version with one command.

Please take note that the use of “-y” is not recommended for yum operation. Surely you have some time to review the packages to be installed on your system by using “yum update” before allowing yum to proceed. In earlier version of CentOS, we are required to restore all programs and data but now with CentOS 7, we can upgrade directly, that being said that unexpected situation still possible, therefore, it is recommended to create a full backup of your server one time before upgrading process.

Follow the below steps to update or upgrade CentOS version.

1. First of all check the current version of your running CentOS using below command.

# cat /etc/redhat-release
CentOS Linux release 7.1.1503 (Core)

2. Take backup of important Data and directory (Example: /etc, /var, /opt). I suggest, for VMware virtual machines, take a good vmware snapshot or run a full backup of the operating systems and data. (MySQL, Apache, NGINX, DNS or etc).

3. Now upgrade with yum update command as shown below.

# yum clean all
# yum update

4. After successfully upgrade reboot the system using below command.

# reboot

5. Now verify the system current running CentOS version.

# cat /etc/redhat-release
CentOS Linux release 7.3.1611 (Core)

You can see above your system has been upgraded successfully.