What system was developed to address the different types of storage needs a cloud consumer may require for availability response times backups and?

What is cloud computing? “Cloud computing is a model for enabling ubiquitous, 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”.1

Some of the words in the above definition are very interesting. Most of the words in the definition are self-explanatory except possibly the word “ubiquitous” that means all pervasive or universal. Yes, as we can find the real clouds everywhere, so the cloud infrastructure can be anywhere. While the words “ubiquitous,” “convenient,” “on-demand,” “configurable,” “rapidly provisioned or released,” and “minimal management effort or service provider interaction” highlight the benefits of the cloud, according to our opinion, the words to be watched carefully are “ubiquitous,” “shared pool,” “configurable resources,” and “minimal management effort or service provider interaction” as these also indicate the need for higher security consideration.

Cloud computing can be discussed around its three Service Models and four Deployment Models.1 The three Cloud Service Models are:1

• Software as a Service (SaaS)

• Platform as a Service (PaaS)

• Infrastructure as a Service (IaaS)

The four Deployment Models are:1

• Private Cloud

• Public Cloud

• Community Cloud

• Hybrid Cloud

Cloud Service Models

As mentioned previously there are three different Cloud Service Models: Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). The details of each of these and the interaction among them are explained in the following section.

Software as a Service (SaaS)

Software applications or products are developed by different vendor organizations by investing substantially in the conceptualization, research, design, development, and testing. The development process would not have been smooth. They would have gone through many dilemmas in the process, including:

• whether to go in for all functionalities planned upfront or to develop and release the product with features in phases;

• which technology to go in for – whether cheaper or costlier, whether simple or complicated;

• which operating system to be chosen as the platform for the application – whether open source like Linux or the popular one like Windows;

• who should be the targeted users; what factors like the usability, scalability, flexibility, response times, maintainability, portability, etc. to be considered (of course, unfortunately, most of the times security as a factor is hardly considered);

• whether to deploy the new resources to develop it or to hire experienced people to develop it.

Considering the infrastructure costs, development tool licensing costs, and human resources salary the total investment, often tends to be substantial. Hence, the pricing of the product will also be substantial unless the product is targeted for mass market. Added to that, the required marketing and sales efforts are huge and they cost significantly. At the end of all these, it is difficult to still say whether the product will be successfully sold and if successfully sold, whether it will be a successful product that will continue to be in demand or by the time the product comes out in the market, some other competitor has come up with a better product and may be, with even better pricing.

The cloud-based Software as a Service (SaaS) has become a handy tool for application providers to rent out their software applications by hosting them on the cloud. Through this, they can make the software application readily available to organizations and users on demand. They can also attract more users as the price per user comes down substantially. Further, enabling additional instances of the same application software or installation of software application additionally for a particular organization is very easy for the vendor organization. This brings down the total cost of marketing, sales, installation, and maintenance of the application software. Again, it is very easy for such vendors to patch / update the software applications in case of any security issues or bugs. Further, because of the pay-as-you-use mode which is applied to the customers, the vendor organizations get a steady stream of revenues instead of the ups and down in the revenue realization because of the traditional sales efforts.

For the users, it is cost effective as the cost of renting is comparatively less than the cost of outright purchase. Further, they will pay as they use and not upfront. They can also increase and decrease the number of users as they scale higher thus not locking up funds in unused software application licenses. More importantly, they need not have dedicated servers and other infrastructure to install and use such software applications in-house. In addition, most of the time, the consumer just has to provide the user with a web browser or a thin client interface. The end user platforms can be, for the most part, smartphones or tablets. This makes the entire proposition very attractive to the consumer organizations.

Software as a Service (SaaS) is defined as: “The capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure. The applications are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email), or a program interface. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user- specific application configuration settings”.1

The advantage of SaaS is that the control on the appropriate configuration of applications lies with the cloud consumer. Other than this, most of the control, from the network to the servers to the operating systems, lies with the cloud provider. Some of the examples of SaaS are SalesForce.com, QuickBooks, Zoho Office Suite, justcloud.com, Dropbox, and many more similar applications.

Platform as a Service (PaaS)

PaaS is “The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.”1

Many of the organizations in the IT industry are in the business of developing software frameworks or software application products, utilities, or tools. They require the infrastructure to develop these software applications, design and development tools, and testing tools to test their output. All these are costly and when added to the cost of human resources, add up to a significant cost to organizations. This has sometimes led companies to use pirated developmental tools which in turn have led to bugs in the outputs, security issues, and violation of laws.

PaaS allows organizations to rent the design, development, and testing platforms, software, and utilities at significantly less cost and often in a pay-per-use structure of payment, At any point of time, depending upon the need, they can move from one platform to another platform if they change course. This would have been possible only at additional cost in a traditional scenario where the organizations have to purchase the design and development frameworks / tools. Also, the number of resources using such tools can be increased or decreased on an as needed basis. Another significant advantage is that some of the design and development tools which are new and which could not have been used by the organizations because of the exorbitant costs now become affordable to the consumer organization. These advantages are significant particularly for smaller organizations with limited funding and resources.

As mentioned in the definition, PaaS may also be used to deploy acquired applications in addition to the consumer created applications. Here, the application developer does not have much control over the underlying environment except for setting configurations on application hosting environment and full control over deployed applications. All other controls on the entire underlying infrastructure, including the storage, lie with the cloud provider. Sometimes, this may constrain the designers and developers to use the provided infrastructure and thus compromise even though they wanted a better underlying infrastructure.

Some of the examples of PaaS are Force.com platform, Windows Azure Platform, Google Apps, and Google Apps Engine.

Infrastructure as a Service (IaaS)

IaaS is defined as: “The capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls).”1

Every organization usually invests heavily in data centers wherein servers are installed, servers are connected through networks, desktops and laptops are installed with the corresponding client software, other infrastructure like physical security, logical security including access control is implemented. The required support infrastructure like IT Managers to System Administrators to support vendors to support systems like generators, UPS, and other backup mechanisms are deployed. All these come at a significant capital expenditure upfront and even more cost to maintain.

IaaS comes in handy here as it eliminates the investment in the infrastructure in data centers, servers, high-end network equipment, storage equipment, and supporting utility infrastructure including physical security like access control. Again, the pay as you use comes in handy to the users. In the traditional scenario, once the investment is made by the organization, it is stuck to it even when the business decreases whereas in the cloud infrastructure scenario, it can requisition additional infrastructure on an as needed basis and release unused or additional infrastructure if the business decreases. This provides for significant financial leverage to the organization. Further, you need not have sophisticated personnel to maintain your IT infrastructure, physically and logically support your systems. You are also less likely to be hit by malicious infections as you have very lean IT infrastructure on your premises. Further, most of the infrastructure management headache is taken over by the cloud provider. On the other hand, if the cloud gets a malicious infection you are hit significantly as such infection can spread quickly to your internal organization unless the cloud provider has significant security controls built into the infrastructure.

With IaaS, organizations have very limited control over the underlying core infrastructure except the operating systems, the applications deployed thereon and related storage most of the times. Virtualization has enabled the entire game of cloud infrastructure (IaaS) provision. A single physical server (i.e., hardware) is logically partitioned to many different virtual servers and provisioned to various consumer organizations depending upon their requirement. A high number of servers are horizontally deployed to provide for large requirements of customers, at the same time, catering to the smaller requirements from smaller organizations, thus building a huge capacity by the cloud provider.

Basically, in this type of cloud provision, the control over Virtual Machine Monitor (VMM), underlying hardware (i.e., physical infrastructure), and network infrastructure lies with the cloud provider. However, depending upon the cloud deployment models chosen by the organization, controls that are available with the consumer organization may vary substantially.

Some of the examples of IaaS are: Amazon Elastic Compute Cloud, RackSpace Cloud, Eucalyptus, and GoGrid.

The various types of cloud service models, namely SaaS, PaaS, and IaaS, and the relationship among them from the control perspective of both customer and vendor, are illustrated in Figure 13-4.

Cloud Computing Service Models Structure

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