Infrastructure as a service

Infrastructure as a Service (IaaS) is the delivery of computer infrastructure (typically a platform virtualization environment) as a service.

These 'virtual infrastructure stacks' [ [http://www.cbronline.com/article_feature.asp?guid=E66B8BF0-43BB-4AB1-9475-5884D82C897F IT as a Service is a model ripe for adoption] ] are an example of the everything as a service trend and shares many of the common characteristics. Rather than purchasing servers, software, data center space or network equipment, clients instead buy those resources as a fully outsourced service. The service is typically billed on a utility computing basis and amount of resources consumed (and therefore the cost) will typically reflect the level of activity. It is an evolution of web hosting and virtual private server offerings.

History

The original term "Hardware as a Service (HaaS)" was first coined by the economist Nicholas Carr in RoughType, Mar 2006 [ [http://www.roughtype.com/archives/2006/03/here_comes_haas.php Nicholas Carr Here Comes HaaS] ] but this has essentially been superseded by "Infrastructure as a service (IaaS)" (which started to circulate in late 2006 with firms such as Savvis [ [http://www.savvis.net/NR/rdonlyres/C9928B45-B9F0-44EA-B954-F287576AF3ED/15494/CIOServicesOrientedIT.pdf Savvis The Rise of Services-Oriented IT] December 2006] , BlueLock [ [http://www.bluelock.com/resources/faq.html BlueLock What is Infrastructure as a Service] October 2006] , ZDNet [ [http://news.zdnet.com/2036-2_22-5604571.html ZDNet Infrastructure as a Service] October 2006] , and Tier 3 [ [http://www.tier3.com Tier 3 IaaS Extend and Centralize] ] ).

Key components

Implementations typically include the following layered components:

* Service level agreements (optional)
* Utility computing billing (eg per instance hour)
* Platform virtualization environment for running client specified virtual machines
* Computer hardware (typically set up as a grid for massive horizontal scalability)
* Computer network (including firewalls, load balancing, etc.)
* Internet connectivity

Key characteristics

The key characteristics of "Infrastructure as a service" includeFact|date=July 2008:

* Resources delivered as a service including servers, network equipment, memory, CPU, disk space, data center facilities,
* Dynamic scaling of infrastructure which scales up and down based on application resource needs
* Variable cost service using fixed prices per resource component
* Multiple tenants typically coexist on the same infrastructure resources
* Enterprise grade infrastructure allows mid-size companies to benefit from the aggregate compute resource pools

Examples

* Amazon EC2

See also

* Cloud computing
* Everything as a service

References