Defining Cloud Computing

Two essential concepts of Cloud Computing are:

Abstraction: Cloud computing abstracts the details of implementation from end users/developers. For example when an application is deployed over cloud it may exist on multiple servers spanning over multiple locations. Similarly, data may be stored in locations that are unknown to the user and Administration may be outsourced to other organizations. Basically, behind the scenes a lot may be happening in the paradigm of cloud computing but the user is exposed only to a abstracted form.

Virtualization: Cloud Computing Virtualizes resources by pooling and sharing resources. It creates different virtual environments for different users. From an user point of view they will not notice any difference between a virtual environment and a dedicated computer. However, behind the scenes cloud computing may be using the same physical machine for multiple Virtual Environments. This is how it pools and shares resources.

As mentioned in previous post there are different classes of cloud computing. One that is based on Deployment Model and the other that is based on the service model. Below are the different kind of Deployment and Service Models.

Deployment Models

• Public
• Private
• Hybrid
• Community

Service Models

• Infrastructure as a Service
• Platform as a Service
• Software as a service

Note: Not all applications benefit from deployment over cloud. The areas that are of concern are Latency, Transaction control, Security and in some cases regulatory compliance. 

Examples of IAAS services providers are:

• Amazon Elastic Compute Cloud (EC2)

• Eucalyptus

• GoGrid

• FlexiScale

• Linode

• RackSpace Cloud

• Terremark
 

A PaaS service adds integration features, middleware, and other orchestration and choreography services to the IaaS model.

Examples of PaaS services are:

• Force.com

• GoGrid CloudCenter

• Google AppEngine

• Windows Azure Platform 

Examples of SaaS cloud service providers are:

• GoogleApps

• Oracle On Demand

• SalesForce.com

• SQL Azure 
Although the line between IAAS, PAAS and SAAS is hazy a cloud reference model like the below figure will give an idea of the services that are provided by vendors as part of these models.

 

A IAAS provider has to develop their own data center throughout the world. Preferably data center should be established in a site where the below facilities are available:

• Have access to low cost power
• Leverage renewable power source
• Be near abundant water
• Be sited where high-speed network backbone connections can be made
• Keep land costs modest and occupation unobtrusive
• Obtain tax breaks
• Optimize the overall system latency

A per U.S. National Institute of Standards and Technology (NIST) the cloud computing system must offer the following characteristics:
> On-demand Self Service - A client should be able to perform additional computing resources without depending on the vendor service personnel.

> Broad Network Access - Access to resources over cloud should be available using standard methods in a manner that provides platform independent access to clients of all types.

> Resource Pooling - A cloud service provider creates resources that are pooled together in a system that supports multi-tenant usage.

> Rapid Elasticity - Resources can be rapidly and elastically provisioned.

> Measured service  - The use of cloud system resources is measured audited and reported to the customer based on a metered system.

The above are the five core characteristics of cloud computing. There are some additionakl advantages of cloud computing as listed below:

• Lower cost
• Ease of utilization
• Quality of service
• Reliability
• Outsourced IT management
• Simplified maintenance and upgrade
• Low barrier to entry

Some of the disadvantages of Cloud computing are:

• Inherent latency
• Stateless system
• Privacy and Security
• Vendor Lock-in

As big vendors have come up with their own proprietary standards so there is a risk that a customer of these Vendors may get locked in with a vendor. Due to these issues there is a strong push in the Cloud Industry to come with a open standard based cloud.

The open-source cloud computing industry is working with the below architectural standards:

• Platform virtualization of resources
• Service-oriented architecture
• Web-application frameworks
• Deployment of open-source software
• Standardized Web services
• Autonomic systems
• Grid computing

Rackspace.com, one of the large IaaS cloud service providers, announced in July 2010 that it is initiating an open-source project called OpenStack that will begin with the code used to run its Cloud Files and Cloud Servers technologies. NASA has also contributed to this by donating some of its Nebula cloud platform technology.

As per Openstack's website OpenStack is a cloud operating system that controls large pools of compute, storage, and networking resources throughout a datacenter, all managed through a dashboard that gives administrators control while empowering their users to provision resources through a web interface.

 



Cloud computing is particularly valuable because it shifts capital expenditures into operating
expenditures. Any application or process that benefits from economies of scale, commoditization of assets, and conformance to programming standards benefits from the application of cloud computing.



These are the unique characteristics of an ideal cloud computing model:

• Scalability: You have access to unlimited computer resources as needed.
This feature obviates the need for planning and provisioning. It also enables batch processing,
which greatly speeds up high-processing applications.

• Elasticity: You have the ability to right-size resources as required.
This feature allows you to optimize your system and capture all possible transactions.

• Low barrier to entry: You can gain access to systems for a small investment.
This feature offers access to global resources to small ventures and provides the ability to
experiment with little risk.

• Utility: A pay-as-you-go model matches resources to need on an ongoing basis.
This eliminates waste and has the added benefit of shifting risk from the client.

The laws of cloudonomics:

Joe Wienman of AT&T Global Services has concisely stated the advantages that cloud computing offers over a private or captured system. A summary of Wienman's “10 Laws ofCloudonomics” are as follows:

 1. Utility services cost less even though they cost more.
Utilities charge a premium for their services, but customers save money by not paying for services that they aren't using.

2. On-demand trumps forecasting.
The ability to provision and tear down resources (de-provision) captures revenue and lowers costs.

 3. The peak of the sum is never greater than the sum of the peaks.
 A cloud can deploy less capacity because the peaks of individual tenants in a shared system are averaged over time by the group of tenants.

4. Aggregate demand is smoother than individual.
Multi-tenancy also tends to average the variability intrinsic in individual demand because the
“coefficient of random variables” is always less than or equal to that of any of the individual
variables. With a more predictable demand and less variation, clouds can run at higher utilization rates than captive systems. This allows cloud systems to operate at higher efficiencies and lower costs.

5. Average unit costs are reduced by distributing fixed costs over more units of output.
Cloud vendors have a size that allows them to purchase resources at significantly reduced prices.

6. Superiority in numbers is the most important factor in the result of a combat (Clausewitz).
Weinman argues that a large cloud's size has the ability to repel botnets and DDoS attacks better than smaller systems do.

7. Space-time is a continuum (Einstein/Minkowski).
The ability of a task to be accomplished in the cloud using parallel processing allows real-time
business to respond quicker to business conditions and accelerates decision making providing a measurable advantage.

8. Dispersion is the inverse square of latency.
Latency, or the delay in getting a response to a request, requires both large-scale and multi-site
deployments that are a characteristic of cloud providers. Cutting latency in half requires four times the number of nodes in a system.

9. Don't put all your eggs in one basket.
The reliability of a system with n redundant components and a reliability of r is 1-(1-r)n. Therefore, when a datacenter achieves a reliability of 99 percent, two redundant datacenters have a reliability of 99.99 percent (four nines) and three redundant datacenters can achieve a reliability of 99.9999 percent (six nines). Large cloud providers with geographically dispersed sites worldwide therefore achieve reliability rates that are hard for private systems to achieve.

10. An object at rest tends to stay at rest (Newton).
Private datacenters tend to be located in places where the company or unit was founded or acquired. Cloud providers can site their datacenters in what are called “greenfield sites.” A greenfield site is one that is environmentally friendly: locations that are on a network backbone, have cheap access to power and cooling, where land is inexpensive, and the environmental impact is low. A network backbone is a very high-capacity network connection. On the Internet, an Internet backbone consists of the high-capacity routes and routers that are typically operated by an individual service provider such as a government or commercial entity. 


Joe Weinman has expanded on these ideas and some others to formulate ten more “laws” for cloud computing adoption based on human behavior.
 
The “10 Laws of Behavioral Cloudonomics” are summarized below:

1. People are risk averse and loss averse.
Ariely argues that losses are more painful than gains are pleasurable. Cloud initiatives may cause the concerns of adoption to be weighed more heavily than the benefits accrued to improving total costs and achieving greater agility.

2. People have a flat-rate bias.
Loss aversion expresses itself by preferences to flat-rate plans where risk is psychologically
minimized to usage-based plans where costs are actually less.

3. People have the need to control their environment and remain anonymous.
The need for environmental control is a primal directive. Loss of control leads to “learned
helplessness” and shorter life spans.

4. People fear change.
Uncertainty leads to fear, and fear leads to inertia. This is as true for cloud computing as it is for
investing in the stock market.

5. People value what they own more than what they are given.
This is called the endowment effect. It is a predilection for existing assets that is out of line with
their value to others. The cognitive science behind this principle is referred to as the
choice-supportive bias.

6. People favor the status quo and invest accordingly.
There is a bias toward the way things have been and a willingness to invest in the status quo that is out of line with their current value. In cognitive science, the former attribute is referred to as the status quo bias, while the latter attribute is referred to as an escalation of commitment.

7. People discount future risk and favor instant gratification.
Weinman argues that because cloud computing is an on-demand service, the instant gratification factor should favor cloud computing.

8. People favor things that are free.
When offered an item that is free or another that costs money but offers a greater gain, people opt for the free item. Weinman argues that this factor also favors the cloud computing model because upfront costs are eliminated.

9. People have the need for status.
A large IT organization with substantial assets is a visual display of your status; a cloud deployment is not. This is expressed as a pride of ownership.

10. People are incapacitated by choice.
The Internet enables commerce to shift to a large inventory where profit can be maintained by many sales of a few items each, the so-called long tail. When this model is applied to cloud computing, people tend to be overwhelmed by the choice and delay adoption.