My Article to FOSSUser - "Ubuntu on Cloud" Part 2

There are three main services of Cloud computing identified. The term services in cloud computing is the concept of being able to use reusable, fine-grained components across a vendor’s network. This is widely known as “as a service.”

§  SaaS ( Software as a Service )

This basically means the software which is there in the cloud. Applications delivered as a service to end users over the Internet. This model is the earliest model of cloud computing in which software companies started to sell their solutions to businesses based on the number of users with a given set of service-level requirements. With SaaS, Customers don’t pay for owning the software; rather, they pay for using it. SaaS provides network-based access to commercially available software. Since the software is managed at a central location, customers can access their applications wherever they have web access.

There are many organizations do service oriented services in the cloud, the big names follows as Oracle (with its CRM on Demand solution), Salesforce.com, and Google (with its Google Apps).

§  PaaS (Platform as a Service)

PaaS is also an application delivering model as like SaaS. But how it differs from SaaS is that, this platform is responsible for operating and organizing all the resources which are to build applications and services completely from the internet, doesn’t require a download or installation software.

Well, the concept PaaS can be easily narrowed down like this. Imagine you’re using NetBeans or Eclipse for your development purpose. So that IDE is simply your development environment. As simple as that, PaaS is a development environment offered as a service in order to create custom applications by the developer. For more info, developer is using the vendor’s “Building Blocks” to create his apps. It is very easy and cool to create apps here, because, of the predefined codes and its integrations.
The PaaS layer is a pretty quite recent addition. PaaS is responsible for providing complete virtualization of the infrastructure (i.e., for making all of these resources appear to be as simple as a single server).
How well that is done will greatly influence the complexity, cost, and effectiveness of both the operations and any efforts to construct (in whole or in part) software applications.
In addition, it is at this layer where it is most logical to easily ensure reliability for both cloud applications and storage.

Amazon Elastic Compute Cloud (EC2) and Savvis are the prominent providers of this model of cloud service. Google App. Engine is very popular for PaaS integration in the recent past.

§  HaaS (Hardware as a Service)

The next type of cloud model is HaaS; it is often called as IaaS (Infrastructure as a Service). This model is not providing any sort of services to the users or developers, but, importantly it offers the hardware that the organization needs when and where. HaaS allows the service providers to “rent” the hardware resources. You can rent Server space, Network equipments, Memory, CPU cycles, Storage space and etc. Based on the organization need the infrastructure can be dynamically altered. Also multiple tenants can be included on to the equipment that you’re renting. There are several guidelines about HaaS and its services.

Service level protocols, Hardware, Network, Internet connectivity, Platform virtualization environment and Utility computing billing are some of them. Service level protocols explain about an agreement between the HaaS providers and clients to ensure a certain level of performance by the system and the hardware. Platform virtualization environment enables the users to run virtual machines on the system. We will have a broad view about virtualization later in the article. Utility computing billing is a set-up which charges the user upon the usage of the resources.

Amazon EC2 is the prominent provider of this model of cloud service. We will also have a broad view Amazon EC2 in the latter part of the article.

There are four deployment models that have been identified in the cloud computing paradigm. They are Public Cloud, Private Cloud, Hybrid Cloud and Community Cloud. 

Public cloud is a model which can be defined as pure cloud. As Wikipedia says, a public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet. Public cloud services may be free or offered on a pay-per-usage model.
But there are many draw-backs in Public cloud where the industry has gone to Private cloud.

         

         Continued on Part 3

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