How do I upgrade CentOS Linux from version 5.3 to latest version 5.4 over the Internet?

CentOS Linux v5.4 has been released and available via mirrors for immediate update. The new version includes the kernel-based virtual machine (KVM) virtualization, next generation of developer features and tools including GCC 4.4, a new malloc(). Also included clustered, high-availability filesystem to support Microsoft Windows storage needs on CentOS Linux.

Step # 1: Make A Backup

It cannot be stressed enough how important it is to make a backup of your system before you do this. Most of the actions listed in this post are written with the assumption that they will be executed by the root user running the bash or any other modern shell. Use the following tools to backup data to other server:

• Use mysqldump for MySQL databases
• Use pg_dump for PostgreSQL databases
• Use tar and rsync tool for LAMP

Step # 2: Update All Packages

Type the following command to get a list of packages that are going to be updated, enter:
# yum list updates
To upgrade your box, enter:
# yum update

Reboot the server:
# reboot

Verify everything is working:
# uname -a
# netstat -tulpn
# tail -f /var/log/messages
# tail -f /path/to/log/file
# cat /etc/redhat-release
Sample outputs:

CentOS release 5.4 (Final)

Or you can use the lsb_release command:
# lsb_release -a
Sample outputs:

LSB Version:	:core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID:	CentOS
Description:	CentOS release 5.4 (Final)
Release:	5.4
Codename:	Final

To view log of all updated package, enter:

tail -f /var/log/yum.log
less /var/log/yum.log
grep -i bind /var/log/yum.log