How to migrate RedHat 5 to RedHat 6/7/8 (RHEL)

A common task for an administrator is to upgrade the Linux operating system. In many circumstances, it is best not to update the existing system – instead choosing to create a new server and migrate everything over to the new server.

The following process will explain how to do this:

Build new Red Hat (RHEL) 7 server

• First and foremost you need to start with a clean installation of the Red Hat Operating system.
• Download the ISO image from your Red Hat subscription page.
  https://access.redhat.com/downloads/
• Install the operating system to a physical or virtual server
• Licence the server using subscription-manager register and attach to an active licence
• Patch the operating system to the latest level using sudo yum update -y

Rsync critical system files from source server

The next step is to install rsync using yum install rsync and synchonsining the following locations:

Note – change the IP below to your server details

sudo rsync -av /home [email protected]_server_ip:/
sudo rsync -av /etc/cron* [email protected]your_server_ip:/
sudo rsync -av /opt/ext [email protected]your_server_ip:/
sudo rsync -av /etc/passwd [email protected]your_server_ip:/
sudo rsync -av /etc/shadow [email protected]your_server_ip:/
sudo rsync -av /opt/ext [email protected]your_server_ip:/

sudo rsync -av /root/certs [email protected]your_server_ip:/

Install and configure SAR

You may need to have SAR system monitoring installed yum install sar