Apress, 2010 by Rytis Sileika
The scope of the system administrator role has changed dramatically over the years. The number of systems supported by a single engineer has also increased. As such, it is impractical to handcraft each installation, and there is a need to automate as many tasks as possible. The structure of systems varies from organization to organization, therefore system administrators must be able to create their own management tools. Historically, the most popular programming languages for these tasks were UNIX shell and Perl. They served their purpose well, and I doubt they will ever cease to exist. However, the complexity of current systems requires new tools, and the Python programming language is one of them.
Python is an object oriented programming language suitable for developing large-scale applications. Its syntax and structure make is very easy to read, so much so that the language is sometimes referred to as executable pseudocode. The Python interpreter allows for interactive execution, so in some situations, you can use it instead of a standard UNIX shell. Although Python is primarily an object-oriented language, you can easily adopt it for procedural and functional styles of programming. Given all that, Python makes a perfect fit as a new language for implementing system administration applications. There are a large number of Linux system utilities already written in Python, such as the Yum package manager and Anaconda, the Linux installation program.
This book is about using the Python programming language to solve specific system administration tasks. We will look at the four distinctive system administration areas: network management, web server and web application management, database system management, and system monitoring. Although I will explain most of the technologies used in this book in detail, bear in mind that the main goal of this book is to show you the practical application of the Python libraries to solve rather specific issues. Therefore, Iβm assuming that you are a seasoned system administrator.
As we go along with the examples, you will be asked to install additional packages and libraries. In most cases, I provide the commands and instructions to perform these tasks on a Fedora system, but you should be ready to adopt these instructions to the Linux distribution that you are going to use. Most of the examples work without many modifications on a recent OS X release (
10.6.X) too.
I also assume that you have a background in the Python programming language. I will be focusing on introducing the specific libraries that are used in system administration tasks as well as some lesser known or less-often-discussed language functionality, such as the generator functions or the class internal methods, but the basic language syntax is not explained. If you want to refresh your Python skills I would recommend Beginning Python: From Novice to Professional, Second Edition by Magnus Lie Hetland (Apress, 2008).
All examples presented in this book assume the Python version 2.6 and will not work correctly with the latest Python 3 without additional modifications. Most of the examples rely on additional modules that have not yet been ported to this version of Python.