Renting Infrastructure in Cloud Computing

9 of 17 in Series: The Essentials of Services in Cloud Computing

Infrastructure as a Service (IaaS) is the delivery of computer hardware (servers, networking technology, storage, and data center space) as a service. You also can expect it to include the delivery of operating systems and virtualization technology to manage the resources. The IaaS customers rent computing resources instead of buying and installing them in their own data center.

Why do companies rent external infrastructure to run their Web sites? All reasons are related to price, aggregation of resources, speed to deployment, and security.

If you look at the Internet service provider (ISP) business model and technology infrastructure, you see a lot of similarities to the IaaS model. In fact, if you compare what customers get from an ISP to what they get from an IaaS vendor, you see that it's pretty much the same capability. Both rent infrastructure for the purpose of running applications.

Therefore, the good news is that infrastructure as a service is actually the maturation of the ISP model. The key difference is the addition of new technologies such as virtualization and well-defined self-service management interfaces.

Taking price beyond hardware with IaaS

At the time of this writing, you can rent a Quad Core Xeon server running at 2.4 GHz with 8GB of memory and 250GB of disk space for about $300 per month. That’s $3,600 per year. A server of this kind doesn’t cost a great deal (say $2,000-$3,000), but if you’re going to use it as a Web server, the cost of ownership will most likely be significantly more than $3,600 per year when you take into account the networking, Internet connections, server management, and everything else the ISP provides.

Managing traffic with IaaS

The ISP not only aggregates server resources but also networking resources, disk space, and bandwidth. Consequently, the ISP customer no longer needs to be concerned about these resources as long as the contract indicates adequate resources to handle spikes in demand. This can be a particular concern for Web sites, which are sometimes subjected to flash floods of traffic; an ISP may not be prepared to scale on demand to meet additional demand for network bandwidth and computer capacity.

Deploying faster with IaaS

The ISP and its successor in the IaaS market typically allocate resources from a pool and therefore it’s usually fast to make new resources available. Normally, when you buy a service or more capacity, it’s available almost instantly (within hours). Because these providers aggregate homogeneous resources across large numbers of customers, it can normally make new resources available faster than the typical data center can. This includes providing a ready-to-run server (or virtual server) that is normally created from a standard software image suitable for a Web server.

Security is variable depending on provider

Service providers may vary in the actual level of security they provide. However, they will know about Internet security, and larger ISPs may be prepared for and able to deal with Internet-specific threats such as denial of service attacks.

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The Essentials of Services in Cloud Computing

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