CLOUD: The NIST Definition

POINTS from

Cloud Computing Explained

By Rosalyn Metz

Three organizations' definitions come to the forefront when defining the cloud: Gartner, Forrester, and the National Institutes of Standards and Technology (NIST). Although both Gartner¹ and Forrester² provide definitions of cloud computing, the NIST definition³ is concise and uses industry-standard terms.⁴

NIST defines cloud computing as:

• ...a model for enabling convenient, on-demand network access
• to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services)
  
• that can be rapidly provisioned and released with minimal management effort or service provider interaction.
  
• This cloud model promotes availability and is composed of five essential characteristics, three service models, and four deployment models.⁵
  

Characteristic: On-Demand Self-Service

When an institution develops or deploys a new application, they first must jump through a number of hoops. For example, if an institution decides they would like to install the learning management system Moodle, they might have to order a server, wait for the vendor to ship it, install the server in the data center, provision an IP address for the server, set up the DNS for the new IP address, install the operating system, etc.

While virtualization tools have improved this workflow dramatically, the process can still be cumbersome. With cloud-based services, many of these steps can be eliminated. Interaction with the service provider is minimized, and with a few clicks of a button, an application can be up and running in a matter of minutes.

In the example below, I use the cloud-based service Heroku to deploy a basic blog application. Prior to creating the video, I installed Ruby on Rails, Heroku's Ruby Gems, and Git on my computer and developed the application. Once these few simple set-up steps were accomplished, deploying the application into Heroku's cloud took a matter of minutes.

Characteristic: Resource Pooling

With current systems and data centers, IT departments often get stuck in a silo of their own creation. Institutions rarely share computing resources, and if they do, it is cumbersome to create and manage workflows that utilize these shared resources.

With the cloud, multi-tenancy rules. Users of the cloud can provision computing resources based on their needs, and then destroy those resources, giving them back to the shared pool once their needs are met. Additionally, users can share resources amongst themselves. For example, if an institution has developed a new piece of software and would like to share it with other institutions, they can create a template for that system in the cloud and allow other institutions to use that template as they see fit.

This example demonstrates Amazon's Elastic Compute Cloud, or EC2. This service allows IT departments to choose from a shared pool of Amazon Machine Images (AMIs) and start up a server with a few clicks. AMIs offer users of Amazon EC2 a quick and easy way to set up systems and servers, with little to no intervention from channels one might normally need to go through.

Characteristic: Rapid Elasticity

Systems change constantly. To create the best experience for users, IT departments often must scale or update systems to meet user demand. Scaling or upgrading a system currently in production can be cumbersome and resource intensive for an IT department.

The cloud provides ways of rapidly scaling to meet user demand. If a system requires more computing resources, an IT department can easily scale the technology to meet those demands. For IT departments that use the cloud, it seems as if they have an endless supply of computing resources available.

In the video below, I use Suchi Software's S3Fox Organizer, a Firefox add-on, to access Amazon Web Services' Simple Storage Solution (S3). S3 allows users to upload files to Amazon's servers and access those files through Amazon web addresses or API calls. S3 plug-ins are available for the blogging software WordPress and the web-based project management application Redmine. In addition to its use within applications, S3 is often used to back up files. A number of scripts,⁶ add-ons,⁷ and plug-ins⁸ help you back up your files on any type of server to Amazon S3.

Characteristic: Broad Network Access

Traditionally, software like Microsoft Word or PowerPoint has been offered as client-based software. Users have to install software to their computers and upgrade systems to handle the programs. If you're away from your computer, you may not have access to the software, which can cause frustration.

Today, much of the software we use is available over the Internet. Many people believe that having a resource available via the Internet is the defining characteristic of the cloud, but it is just one of the five characteristics.

In the example here I demonstrate Google Docs, a web-based document creator and editor. Google Docs is a slimmed down version of Microsoft Office, which also has a web-based version known as Microsoft Office Web Apps 2010. Both products allow you to access and edit files from any computer with an Internet connection, eliminating the need for access to a particular computer to edit documents.

Characteristic: Measured Service

To monitor network, server, and application usage, IT departments employ many different monitoring tools and reporting systems. The cloud, however, allows both cloud providers and IT departments to monitor usage. Cloud providers charge IT departments based on their use of computing resources. On the other hand, IT departments can use these metering (or measured) services to scale resources up and down based on information gathered from these particular tools.

The following demonstration discusses a bill from an Amazon Web Services' account. In addition to this bill, I will also briefly discuss Amazon Web Services' CloudWatch, a monitoring tool that not only allows you to monitor your system but also, in conjunction with other services, helps you scale your AWS-based system. Information on Amazon's pricing schema for different services, including CloudWatch, can be found on the Amazon Web Services' website.

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