Architecting for the Cloud: Best Practices

Editor's Notes

1. Explain each service features and details here
2. This is your classic three tier architecture. Incoming requests are fielded by a web server. The web server probably also draws files (such as images, PDFs, music, and so forth) from a file server. The web server farms processing out to a number of servers running an application server. This is where the bulk of your application’s business logic probably resides. You probably maintain a relational database on the back-end as well.
3. Let’s start our migration project by moving many of our static and large files over to Amazon S3. Things like images, music, PDFs, and the like are best suited for Amazon S3. Amazon S3 provides a low-cost, highly reliable and scalable storage environment for your web applications.
4. Many times you’ll have a number of users hitting your web application from all over the world. It can be time consuming and slow to serve all of those users’ requests from Amazon S3. That’s why we built Amazon CloudFront. Amazon CloudFront is a content delivery network that takes the data you’ve stored in Amazon S3 and caches it across a worldwide network of edge locations. In this way, the large static files used by your web application are stored as close as possible to the users who are requesting them.
5. Amazon EC2 enables you to choose the operating system and application platform of your choice to host your web application. Whether it’s Microsoft .NET, IBM WebSphere, JBoss, Oracle Fusion Middleware, PHP, Ruby on Rails, or whatever, you can configure your own virtual environment to run the platform you need for your business. This is where you’ll move your web application, altering it to point to the persistent files you’ve moved to Amazon S3.
6. A typical web application has a front-end web server to field incoming requests, which then farms out work to a bunch of application servers. You can move these applications ervers to Amazon EC2 as well.
7. You’ll also want to move your database into the cloud. Amazon Elastic Block Store is a feature of Amazon EC2 that provides a block storage device in the cloud. You’d house your database in Amazon EBS. Amazon EBS can also be setup to periodically snapshot backup images into Amazon S3, so you can always roll back to a version of Amazon EBS if you need to, and you can rest assured that your database will exhibit the same resilient and reliable characteristics as the rest of AWS.
8. Amazon SQS is a queueing service that provides the glue between your web server and your application server. The most common setup will involve configuring two queues. The first queue will accept messages from the web server hosted on Amazon EC2. Application servers, also hosted on Amazon EC2, will pluck those messages off the queue, process data based on the contents of the message, and then place the equivalent of an “I’m done! Here are the results.” message on the second queue. The web server would then pluck the message off the second queue and return results back to the client that made the initial request. In this way, your Amazon EC2 instances can grow or shrink, startup and fail with impunity, while you can rest assured that all of your data processing happens reliably.
9. Amazon SimpleDB can be added to the equation to store your access logs, application logfiles, and even indices to data you’re storing in Amazon S3.
10. Amazon SimpleDB can be added to the equation to store your access logs, application logfiles, and even indices to data you’re storing in Amazon S3.
11. The day is not too far when applications will cease to be aware of physical hardware. Much like plugging in a microwave in order to power it doesn’t require any knowledge of electricity, one should be able to plug in an application to the cloud in order to receive the power it needs to run, just like a utility. As an architect, you will manage abstract compute, storage and network resources instead of physical servers. Applications will continue to function even if the underlying physical hardware fails or is removed or replaced. Applications will adapt themselves to fluctuating demand patterns by deploying resources instantaneously and automatically, thereby achieving highest utilization levels at all times. Scalability, Security, High availability, Fault-tolerance, Testability and Elasticity will be configurable properties of the application architecture and will be an automated and intrinsic part of the platform on which they are built.However, we are not there yet. Today, you can build applications in the cloud with some of these qualities by implementing the best practices highlighted in the paper. Best practices in cloud computing architectures will continue to evolve and as researchers, we should focus not only on enhancing the cloud but also on building tools, technologies and processes that will make it easier for developers and architects to plug in applications to the cloud easily.