Let’s start by getting the monkey off our back and just say that the book is heavily geared towards Amazon services but he mentions this in this in the very beginning saying that his experience “is mostly with the Amazon cloud, and the Amazon Web Services offering make up the bulk of the market today.”  However, he also specifically mentions that representatives of Rackspace and GoGrid participated in the review process and even provided appendices to provide additional information about the services that each company offers.

Now that that is out in the open Cloud Application Architectures provides a good insight into what you must take into consideration when it comes to cloud computing.  The first two chapters are basic and provide the groundwork for the remainder of the book.  If you are already familiar with the basic concepts of cloud computing you can probably skip the first chapter and similarly with chapter 2 if you have knowledge about Amazon services.

The remaining chapters focus on questions and concerns that should be considered before making the move to cloud computing.  Chapter 3 discusses software licenses, cost comparison, service availability, reliability, and performance, and finally disaster recovery.  Chapter 4 provides a discussion on application design which could be very useful if you are just in the planning stages of your application.  If your application already exists and you are looking to move the application over from an existing system some important questions are brought up:

• How will you manage the state of your application?
• What do you need to do for data security and integrity?
• How do you handle privacy issues?

The final question of privacy can be very important for an application and chapter 4 provides an introduction to designing an application with privacy in mind.

Chapter 5 gets into a much deeper discussion of security and privacy.   The author provides a discussion on the importance of encrypting your data and backing up your data to a different location. These things can be very important to protect your customer’s information in case something ever happens.  One sticky situation for applications is the variety of security and privacy standards (HIPAA, PCI, SOX, etc.) that applications are expected to meet.  Depending on what your application does you may or may not have to comply with these different standards but if you do it is important to know that from the beginning and how the cloud affects each standard.  In the end, the author candidly points out that when these standards were created cloud computing wasn’t taken into consideration; as a result, your application may meet the spirit of the law but you may have to make some adjustments to meet the letter of the law.

The final chapter discusses disaster recovery and scalability.  The author discusses the need to have a monitoring system and provides a few examples of monitoring systems.  One thing that has been introduced since the publication of this book is Amazon’s CloudWatch and AutoScaling.  These two features enable you to scale an application by adjusting the number of servers for your application based on demand.  This can obviously drain the bank if you are not careful but it can also save you if you have a sudden spike in demand for your application.  In addition, the ability to use sticky sessions (maintain an existing session on a specific instance) with the Amazon Load Balancers has recently been released.

The appendices provide a reference to Amazon Web Services, a description of GoGrid, and a description of Rackspace hosting.  The number of players in the cloud computing market has grown and it would be best to do some searching and find the pros and cons of each service according to actual users.  In addition, as is the case with most technology the Amazon reference is outdated and doesn’t include information on CloudWatch, AutoScaling, Loadbalancing, RDS, etc.

Overall this book was a great overview of cloud computing.  It would be great to see a new addition or online addendum that is less Amazon-centric and provides more information regarding other players.  However, this is a great reference whether you are designing a new application or looking to convert an existing application.  After working with cloud computing for over a year I can say that I wish I would have had this book before I started because many of the considerations and concepts that are discussed I have learned about through hard work and sometimes trial and error.