For the computer professional who has considered consolidating server load using any of the popular server virtualization technologies available, William von Hagen’s book is a must read.  We give the book a solid review in the full article.

Professional Xen Virtualization
William von Hagen, 2008
ISBN 978-0-470-13811-3

My purchase of this book was driven by the fact that I was in the middle of trying to learn about Xen, the open source server virtualization platform.  I had read reviews on other books related to Xen and had look at sample chapters or tables of contents.  Most of the other books appeared to be weak on content, or they were out of date (not difficult in the computer industry).

This is not the case with von Hagen’s work.  In a systematic fashion, he begins with the general and works to the specific.  The book opens with an overview of the topic of server virtualization.  This is good material for the IT manager or bean counter who wants the fiscal reasons for moving to this technology.  He also includes a solid review of the many other products and projects available to use for your virtualization platform.  I personally appreciated the sterile, clinical approach von Hagen used in giving the pros and cons of each of the items while ultimately listing the good reasons for choosing Xen as the best alternative.

Professional Xen Virtualization gives good step-by-step examples for building your own virtual servers with Xen, including the very basic levels of understanding the Linux boot process and how to obtain and install the Xen software itself.  My use of Xen is currently limited to hardware virtual machines (HVM) running on newer Intel processors which support virtualization technology.  I ran into a couple of questions with building paravirtualized machines (PVM) and discontinued my exploration since I needed to accelerate my learning of Xen itself related to HVMs.

What I liked about the book was the heart of the content.  As a new user to Xen, I had numerous questions related to configuration, what type of filesystem to use, and (very importantly) how networking functions.  The author gives good examples, clear definitions of configuration file options and easy to understand overviews of how the various parts of Xen and virtual servers function and interoperate.  Furthermore, there are plenty of screenshots, illustrations and other graphics which help to support the text without turning it into a picture book.

I have already used the two appendices repeatedly, as they provide a quick reference to configuration file options and the all-important xm command.  Also, I have incorporated several of the tips von Hagen offers which help make managing a virtual server deployment much easier.  These include naming conventions, filesystem labeling, virtual interface naming and more.

How could the book be improved?  I would like to have seen a more detailed example and overview of routed networking even though the default bridged networking is what most people will use with Xen.  Even though von Hagen gives a respectable treatment to various reasons why a virtual server install may fail or have problems, the next edition of this book should expand on this.  In my case, an apparent bug or default configuration in my operating system of choice resulted in a hard to fix and find networking error which delayed my progress.

That being said, I made tremendous headway in my Xen installation project by the use of this timely book.  I heartily recommend it to anyone considering virtualization in general and Xen in particular.  If you would like to purchase this book, please use our link to Amazon, as it benefits our review site.