Introduction

Cloud Architectures are designs of software applications that use Internet-accessible on-demand services. Applications built on Cloud Architectures are such that the underlying computing infrastructure is used only when it is needed (for example to process a user request), draw the necessary resources on-demand (like compute servers or storage), perform a specific job, then relinquish the unneeded resources and often dispose themselves after the job is done. While in operation the application scales up or down elastically based on resource needs.

Why Cloud Architectures?

Cloud Architectures address key difficulties surrounding large-scale data processing. In traditional data processing it is difficult to get as many machines as an application needs. Second, it is difficult to get the machines when one needs them. Third, it is difficult to distribute and co-ordinate a large-scale job on different machines, run processes on them, and provision another machine to recover if one machine fails. Fourth, it is difficult to auto-scale up and down based on dynamic workloads. Fifth, it is difficult to get rid of all those machines when the job is done. Cloud Architectures solve such difficulties.

Applications built on Cloud Architectures run in-the-cloud where the physical location of the infrastructure is determined by the provider. They take advantage of simple APIs of Internet-accessible services that scale on-demand, that are industrial-strength, where the complex reliability and scalability logic of the underlying services remains implemented and hidden inside-the-cloud. The usage of resources in Cloud Architectures is as needed, sometimes ephemeral or seasonal, thereby providing the highest utilization and optimum bang for the buck.

Business Benefits of Cloud Architectures

There are some clear business benefits to building applications using Cloud Architectures. A few of these are listed here:

• Almost zero upfront infrastructure investment: If you have to build a large-scale system it may cost a fortune to invest in real estate, hardware (racks, machines, routers, backup power supplies), hardware management (power management, cooling), and operations personnel. Because of the upfront costs, it would typically need several rounds of management approvals before the project could even get started. Now, with utility-style computing, there is no fixed cost or startup cost.
• Just-in-time Infrastructure: In the past, if you got famous and your systems or your infrastructure did not scale you became a victim of your own success. Conversely, if you invested heavily and did not get famous, you became a victim of your failure. By deploying applications in-the-cloud with dynamic capacity management software architects do not have to worry about pre-procuring capacity for large-scale systems. The solutions are low risk because you scale only as you grow. Cloud Architectures can relinquish infrastructure as quickly as you got them in the first place (in minutes).
• More efficient resource utilization: System administrators usually worry about hardware procuring (when they run out of capacity) and better infrastructure utilization (when they have excess and idle capacity). With Cloud Architectures they can manage resources more effectively and efficiently by having the applications request and relinquish resources only what they need (on-demand).
• Usage-based costing: Utility-style pricing allows billing the customer only for the infrastructure that has been used. The customer is not liable for the entire infrastructure that may be in place. This is a subtle difference between desktop applications and web applications. A desktop application or a traditional client-server application runs on customer’s own infrastructure (PC or server), whereas in a Cloud Architectures application, the customer uses a third party infrastructure and gets billed only for the fraction of it that was used.
• Potential for shrinking the processing time: Parallelization is the one of the great ways to speed up processing. If one compute-intensive or data-intensive job that can be run in parallel takes 500 hours to process on one machine, with Cloud Architectures, it would be possible to spawn and launch 500 instances and process the same job in 1 hour. Having available an elastic infrastructure provides the application with the ability to exploit parallelization in a cost-effective manner reducing the total processing time.

Examples of Cloud Architectures

There are plenty of examples of applications that could utilize the power of Cloud Architectures. These range from back-office bulk processing systems to web applications. Some are listed below:

• Processing Pipelines
  • Document processing pipelines – convert hundreds of thousands of documents from Microsoft Word to PDF, OCR millions of pages/images into raw searchable text
  • Image processing pipelines – create thumbnails or low resolution variants of an image, resize millions of images
  • Video transcoding pipelines – transcode AVI to MPEG movies
  • Indexing – create an index of web crawl data
  • Data mining – perform search over millions of records
• Batch Processing Systems
  • Back-office applications (in financial, insurance or retail sectors)
  • Log analysis – analyze and generate daily/weekly reports
  • Nightly builds – perform nightly automated builds of source code repository every night in parallel
  • Automated Unit Testing and Deployment Testing – Test and deploy and perform automated unit testing (functional, load, quality) on different deployment configurations every night
• Websites
  • Websites that “sleep” at night and auto-scale during the day
  • Instant Websites – websites for conferences or events (Super Bowl, sports tournaments)
  • Promotion websites
  • “Seasonal Websites” - websites that only run during the tax season or the holiday season (“Black Friday” or Christmas)

Tips for Designing a Cloud Architecture Application

1. Ensure that your application is scalable by designing each component to be scalable on its own. If every component implements a service interface, responsible for its own scalability in all appropriate dimensions, then the overall system will have a scalable base.
2. For better manageability and high-availability, make sure that your components are loosely coupled. The key is to build components without having tight dependencies between each other, so that if one component were to die (fail), sleep (not respond) or remain busy (slow to respond) for some reason, the other components in the system are built so as to continue to work as if no failure is happening.
3. Implement parallelization for better use of the infrastructure and for performance. Distributing the tasks on multiple machines, multithreading your requests and effective aggregation of results obtained in parallel are some of the techniques that help exploit the infrastructure.
4. After designing the basic functionality, ask the question “What if this fails?” Use techniques and approaches that will ensure resilience. If any component fails (and failures happen all the time), the system should automatically alert, failover, and re-sync back to the “last known state” as if nothing had failed.
5. Don’t forget the cost factor. The key to building a cost-effective application is using on-demand resources in your design. It’s wasteful to pay for infrastructure that is sitting idle.Cloud Architectures are designs of software applications that use Internet-accessible on-demand services. Applications built on Cloud Architectures are such that the underlying computing infrastructure is used only when it is needed (for example to process a user request), draw the necessary resources on-demand (like compute servers or storage), perform a specific job, then relinquish the unneeded resources and often dispose themselves after the job is done. While in operation the application scales up or down elastically based on resource needs.
   

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