Building Custom Packages; Building Packages For Red Hat Network; Rpm Benefits - Red Hat NETWORK SATELLITE 5.3.0 - CHANNEL MANAGEMENT Management Manual

Chapter 3.

Building Custom Packages

There are many things that might go wrong when building software packages. This is especially
true when these packages must be delivered and installed through Red Hat Network. This chapter
provides an overview of how to build packages for successful delivery via Red Hat Network. Topics
covered include why to use RPM, how to build packages for RHN, and how to properly sign packages.

3.1. Building packages for Red Hat Network

Red Hat Network uses the RPM Package Manager (RPM) technology to determine what software
additions and updates are applicable to each client system. Packages retrieved from Red Hat Network
are usually in RPM format. Entire ISO images, however, are available through the Software tab of the
Red Hat Network website, but are not available in RHN Satellite Server installations. If your Satellite
has Solaris support enabled, you can use RHN Push to upload Solaris packages to custom channels
used by Solaris clients.
RPM is a tool that provides users with a simple method for installing, uninstalling, upgrading, and
verifying software packages. It also allows software developers to package the source code and
compiled versions of a program for end users and developers.

3.1.1. RPM Benefits

RPM provides the following advantages:
Easy Upgrades
Using RPM, you upgrade individual components of a system without completely reinstalling.
When Red Hat releases a new version of Red Hat Enterprise Linux, users do not have to
reinstall in order to upgrade. RPM allows intelligent, fully-automated, in-place upgrades of your
system. Configuration files in packages are preserved across upgrades so users do not lose
customizations. There are no special upgrade files needed to update a package because the
same RPM file is used to install and upgrade the package.
Package Querying
RPM provides querying options that allows you to search through your entire RPM database for all
packages or just for certain files. You can also easily find out what package a file belongs to and
from where the package came. The files contained in the package are in a compressed archive,
with a custom binary header containing useful information about the package and its contents.
RPM queries the headers quickly and easily.
System Verification
Another feature is the ability to verify packages. If you are worried a file related to a package was
deleted, you can verify the package to check the status of the files it provides. The verification
notifies you of any anomalies. If errors do exist, you can reinstall the files easily. Modified
configuration files are preserved during reinstallation.
Pristine Sources
A crucial design goal of RPM is to allow the use of pristine software sources, as distributed by
the original authors of the software. With RPM, the pristine sources can be packaged, along with
any patches that were used, plus complete build instructions. This is an important advantage for
several reasons. For instance, if a new version of a program is released, you do not necessarily
have to start from scratch to make it compile. You can look at the patch to see what you might
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