DESCRIPTION:
YUM stands for Yellowdog Updater modified.YUM is a default package management in RHEL/CentOS linux. It is used to search install, update and remove necessary rpm files from system. It uses the repository to manage rpm files, where repository is collection of rpm files. As YUM depends on repository, there must be atleast one working repository before it can be used.YUM can automatically resolve software dependencies and based on system hardware it can automatically select appropriate versions of RPM packages from repository.

PREREQUISITIES:
ISO Image file, RPM packages.

REQUIRED SOFTWARE:

YUM-plugin-fastestmirror -1.1.30-30.e16.noarch
Packagekit-YUM-0.5.8-25.e16.x86_64
YUM-plugin-security-1.1.30-30.e16.noarch
YUM-3.2.29-69.e16.CentOS.noarch
Packagekit-YUM-plugin-0.5.8-25.e16.x86_64
YUM utils-1.1.30-30.e16.noarch
YUM-metadata-Parser-1.1.2-16.e16.x86_64

YUM REPOSITORY CONFIGURATION FILE:

YUM repository configuration file:
1. Must be located in /etc/yum.repos.d/directory name.
2. To be recognized by YUM it must have .repo extension.

The available YUM repository configuration file options are :
Repository ID: It must be one word unique ID.
Name: Human readable name
Base URL: URL to repository directory.
Enabled: Enable repository when performing updates and installs.
Gpgcheck: Enable /disable GPG signature checking.
Gpgkey: URL to GPG key.

STEPS OF CONFIGURATION:

STEP 1: First mount cdrom to directory mnt.
mount /dev/cdrom /mnt

STEP 2: Create YUM repository configuration file.
Using vi editor create a new configuration file with .repo extension.
Vi /etc/yum.repos.d/CentOS.repo

STEP 3: Insert YUM repository options.

[Base]
Name =CentOS6
Baseurl=File:///mnt/
Enabled=1
Gpgkey =0