Demystifying Cloud: What is Cloud?

DEMYSTIFYING CLOUD

SRIRAM RANGANATHACHARI

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What is Cloud ?

Cloud computing gets its name from the internet. The internet is represented in network diagrams as a cloud. It is a cluster, a bunch of servers held together by a network. It can also be considered as a supercomputer. Cloud computing cuts down operational and capital costs. It lets IT departments focus on strategic projects instead of keeping the datacenter running.

A cloud can be either a single site cloud or a geo-distributed cloud. A single site cloud consists of servers or compute nodes grouped into racks (unit of several servers which share the same power and a rack switch. These rack switches are further connected to a core switch using a tree topology). There are backend nodes used for storage purposes and frontend nodes for submitting jobs and receiving client requests.

Typically a datacenter is housed in a single building or warehouse in large companies. Large companies may also have multiple geographically distributed datacenters connected to each other. So these are multiple sites, each site being a datacenter. This is often called a geo-distributed cloud.

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History of cloud

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The first computers that were built especially the ENIAC, EDVAC and ELLIAC were the first computers built in the architecture that we know of today. They were datacenters that occupied large halls and labs. They were built in the 1940’s and 50’s.

The 1960’s and 70’s was the era of the time sharing and data processing industry. These computers took large amounts of data in KB or MB and processed it to give outputs.

In 1980’s personal computers became popular and time sharing and data processing declined. PC’s also made it easier to build clusters or workstations. It led to grid computing and very large scaling systems such as peer-peer systems in 1990’s and 2000’s.

Now we have come to cloud processing and datacenter industry by building very large scale clusters that process very large amounts of data and so cloud and datacenter are coming back full circle to 1960’s and 70’s except with a lot more scale and workload.

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Cloud computing

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Cloud computing is a construct that allows you to access applications that actually reside at a location other than your computer or other Internet-connected device; most often, this will be a distant datacenter.

Instead of keeping data on your own hard drive or updating applications for your needs you use a server over the internet at another location, to store your information or use its applications. It is the practice of using a network of remote servers hosted on the internet to store, manage and process data rather than a local server or a personal computer. It refers to the delivery of computing resources over the internet.

Cloud services allow individuals and businesses to use software and hardware that are managed by third parties at remote locations. This means that they handle the costs of servers, they manage the software updates, and—depending on how you craft your contract---you pay less for the service. Examples of cloud services are online file storage, social networking sites, webmail and online business applications.

The characteristics of cloud computing include1. On-demand self service2. Broad network access3. Resource pooling4. Rapid elasticity5. Measured service

On-demand self services means customers can request and manage their own

computing resources. Broad network access allows services to be offered over the internet or private networks. Pooled

resources means that customers draw from a pool of computing resources, usually in

remote data centres.


Components of a cloud

Clients

• Clients are the devices that the end users interact with to manage their information on the cloud. Clients can be either thin clients, thick clients or mobile clients. Thin clients are computers that do not have internal hard drives, but rather let the servers do all the work, but then display the information. Thick clients are regular computers. Mobile devices include PDAs or smart phones, like Blackberry, Windows mobile smart phones or iPhone.

Datacenter

• The datacenter is the collection of servers where the application to which you subscribe is housed. It could be a large room in the basement of your building or a room full of servers on the other side of the world that you access via the Internet. A growing trend in the IT world is virtualizing servers. That is, software can be installed allowing multiple instances of virtual servers to be used. In this way, you can have half a dozen virtual servers running on one physical server.

Distributed servers

• Servers can be located in different geographical locations but to the cloud subscriber they act as if they are located right next to one another. It gives more security options. If something were to happen to one site service would still be accessed through another site.

A cloud computing solution is made up of

three elements: clients, the datacenter, and distributed servers. Each element has a

specific role in delivering functional

cloud computing solution.


Cloud computing and Grid computing

Grid computing applies the resources of numerous computers in a network to work on a single problem at the same time. This is done to address a scientific or technical problem. An example of grid computing is the World Community Grid---Berkeley Open Infrastructure for Network Computing (BOINC). Here one can dedicate one’s idle CPU processing power to help conduct protein-folding experiments in an effort to create better and more durable rice crops to feed the world’s hungry.

Grid computing necessitates the use of software that can divide then send out pieces of the program to thousands of computers.

Grid computing is appealing for several reasons:

• It is a cost-effective way to use a given amount of computer resources.• It is a way to solve problems that need a tremendous amount of computing power.• The resources of several computers can be shared cooperatively, without one computer managing the other.

In grid computing, a large project is divided among multiple computers to make use of their resources. Cloud computing does just the opposite. It allows multiple smaller applications to run at the same time.


ServicesSoftware as a Service (SaaS) is a model in which an application is hosted as a service to customers who access it via the internet. When the software is hosted off-site, the customer doesn’t have to maintain or support it. The provider does all the patching and upgrades as well as keeping the infrastructure running.In SaaS the more you use it the more you are billed, but in some cases you don’t have to pay as much because you are billed based on your use of the application.SaaS applications differ from earlier distributed computing solutions in that SaaS was developed specifically to use web tools, like the browser. This makes them web-native. 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.

Platform as a Service (PaaS) is another application delivery model. PaaS supplies all the resources required to build applications and services completely from the Internet, without having to download or install software.

PaaS services include application design, development, testing, deployment, and hosting. A downfall to PaaS is that if you create an application with one cloud provider and decide to move to another provider, you may not be able to do so—or you’ll have to pay a high price.

Hardware as a Service (HaaS) is the next form of service available in cloud computing. Where SaaS and PaaS are providing applications to customers, HaaS doesn’t. It simply offers the hardware so that your organization can put whatever they want onto it. Rather than purchase servers, software, racks, and having to pay for the datacenter space for them, the service provider rents those resources.

HaaS allows you to “rent” such resources as• Server space• Network equipment• Memory• CPU cycles• Storage space


Deployment of cloud services

In private cloud, the cloud infrastructure is operated for a specific organization and is managed by the organization or a third party. There are many situations where for strategic, operational, or perhaps simply cultural reasons an organization may choose to build and operate their own, private cloud. These private clouds can be built and operated as just what their name implies: a fully functional cloud that is owned, operated, and presumably restricted to a particular organization. In fact, there are an increasing number of software and service offerings designed to facilitate just this—essentially ‘‘private clouds in a box.’’

Customers – individual users or enterprises – access these services over the internet from a third-party provider who may share computing resources with many customers. E.g. services aimed at the general public such as e-mail services or social networking sites. The first clouds of any kind were mostly public clouds, e.g., Google, Amazon, and Salesforce. It is the most common form of cloud computing, in which services are made available to the general public in a pay-as-you-go manner.

As the name implies, a hybrid cloud is a combination of any/all of the other types of clouds.

The idea of a Community Cloud is derived from the Grid Computing and Volunteer Computing paradigms. In a community cloud, several enterprises with similar requirement can share their infrastructures, thus increasing their scale while sharing the cost.

In server virtualization many operating systems can each run on a single physical server at the same time. Each operating system thinks that it has a physical machine entirely to itself. Each operating system is unaware of the other. They each go about doing their business without interfering with the other.

In this way an enterprise can, for example, take many small physical servers (typically scattered both physically as well as organizationally, almost always running at low utilization rates) and consolidate them onto a smaller number of servers, usually centrally located and managed. This is called server consolidation, and has been helpful in battling server sprawl, a bane for many an enterprise. Server sprawl is discussed in more detail later in this section.

Private Cloud Public Cloud

Hybrid Cloud

Community Cloud

Virtualization


Cloud services: The first ones to reach thereAmazonAmazon was one of the first companies to offer cloud services to the public, and they are very sophisticated. Amazon offers a number of cloud services, including :

• Elastic Compute Cloud (EC2)• Simple Storage Service (S3)• Simple Queue Service (SQS)• SimpleDB

MicrosoftMicrosoft’s cloud computing solution is called Windows Azure, an operating system that allows organizations to run Windows applications and store files and data using Microsoft’s datacenters. It also offers Azure Services Platform, which are services that allow developers to establish user identities, manage workflows, synchronize data, and perform other functions as they build software programs on Microsoft’s online computing platform.

Key components of Azure Services Platform include:• Windows Azure• Microsoft SQL Services• Microsoft .NET Services• Live Services• Microsoft SharePoint Services and Microsoft Dynamics CRM Services

There are scores of

vendors who offer cloud

services. What they

have to offer varies based

on the vendor and

their pricing models are

different, as well


When can one use cloud computing

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Compute clouds allow access to highly

scalable, inexpensive, on-demand computing resources that run the

code that they’re given. Compute clouds

are the most flexible in their offerings and

can be used for sundry purposes; it simply

depends on the application the user

wants to access.

COMPUTE CLOUDS

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CLOUD APPLICATIONS

One of the first cloud offerings was cloud storage and it remains a popular solution. Cloud storage is a big world. There are already in excess of 100 vendors offering cloud storage. This is an ideal solution if you want to maintain files off-site

CLOUD STORAGE


Benefits of Cloud Computing

ScalabilityCloud computing can help you manage a huge upswing in computing need. Rather than having to buy, install, and configure new equipment, one can buy additional CPU cycles or storage from a third party.

Knowledgeable VendorsWhen new technology becomes popular, there are plenty of vendors who offer their version of that technology. This isn’t always good, because a lot of those vendors tend to offer less than useful technology. By contrast, the first comers to cloud computing are actually very reputable companies.

SimplicityNot having to buy and configure new equipment allows the IT staff to get right to their business. The cloud solution makes it possible to get an application started immediately, and it costs a fraction of what it would cost to implement an on-site solution

More Internal ResourcesBy shifting the non-mission-critical data needs to a third party, the IT department is freed up to work on important, business-related tasks. You also don’t have to add more manpower and training that stem from having to deal with these low-level tasks.Also, since network outages are a nightmare for the IT staff, this burden is offloaded onto the service provider.

Demystifying Cloud: What is Cloud?

Technology

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