The following introduction to cloud computing was presented during a panel discussion on The State of Startups using Cloud Computing, June 4, 2009[1]. Our objective was to give a brief overview of cloud computing to set context for the panel discussion in no more than 3 minutes. Key points are shown in bold.
Cloud computing shares ancestry with grid computing, computing as a utility, hosted computing, and even peer-to-peer systems. The basic idea is to provide network access to seemingly dedicated computing environments that actually run on shared resources. Under the covers a set of “virtualization” technologies are used to maintain the illusions of a dedicated environment.
As with any emerging market, there is a struggle over terminology and the definition of cloud computing. This struggle is about how a company and its products and services are positioned relative to the emerging market, and whether the company is perceived as being in the new market or “out-of-it”. The most common framework for categorizing cloud services is a takeoff on the long established software-as-a-service nomenclature. The three categories in that framework are Infrastructure-as-a-Service (virtual hardware); Platform-as-a-Service (virtual middleware), and Software-as-a-Service (virtual applications).
Amazon is unarguably the model for an Infrastructure-as-a-Service provider, as Salesforce.com is a model for Software-as-a-Service. Though there are providers in the Platform-as-a-Service space, from Google, Microsoft, Intuit, and others, none stand out as the prototypical model.
Our panel members will talk mostly about their use of Infrastructure-as-a-Service, mainly Amazon’s Web Services, though it will be interesting to see if any on the panel or in the audience see new players gain significant market and mind-share [which they did not].
Amazon’s Web Services consists of a couple of core services: Simple Storage Service (S3) providing HTTP access to storage, and the Elastic Computing Cloud (EC2) providing access to virtual machine environments; and a set of higher level services: Simple Queue Service (SQS) for transferring data messages between machines, SimpleDB, a reduced-function database, Elastic Map-Reduce, based on Hadoop, and CloudFront for content delivery. And, more services are being added. Panelists will describe their use of and experience with these and other cloud services.
A simple example of the use of Amazon’s EC2 illustrates how cloud computing works. With credit card in hand, go to the Amazon EC2 site and select an operating system to use and the type of (virtual) machine you want the operating system to run on. Once the operating system is running, you use a web browser to access and configure the system with additional software that you’ve either developed or acquired. You save and can later retrieve your modified system image to your S3 account. Thereby, you can startup or shutdown your system image on as many virtual machines as you want, you can start as many instances of your environment as you want — each machine has an IP address, so that the machines can communicate with each other within the cloud or with clients and services outside of the cloud. Your credit card will be billed for your hour by hour usage. Thus, you can make frequent adjustments to your aggregate computing capacity. This ability to quickly grow and shrink computing capacity is why Amazon uses the term elastic in Elastic Computing Cloud, and one of the main reasons why this form of cloud computing is so attractive to startup companies. … By the way, if you’re just playing around, don’t forget to shut down your EC2 instance(s) — the servers will happily continue running on idle and you will get billed for this usage.
Of course , managing your cloud usage can become much more complicated than this simple example as you scale up and manage a large number of virtual machine instances. The members of the panel will describe their experiences using cloud computing to support their businesses.
References
[1] The State of Startup Companies Using Cloud Computing, Boston, June 4, 2009.
http://www.vilnashul.org/index.php/events/event/the-state-of-startups-using-cloud-computing
http://www.whiteontech.com/blog/?p=3
http://nedbatchelder.com/blog/200906/realworld_cloud_computing.html