INTRODUCTION TO CLOUD

What is a Cloud ?

Basically when ever we come across the word “Cloud” we think off about the cloud in the sky, but its not about that cloud we are discussing about, its about the cloud in computer. We can think of a while ,why this cloud exists in the computer ?. It is the simple answer, generally “cloud” refers to the servers that are accessed over the Internet, and the software and databases that run on those servers. In the other terms it can be defined as “The Cloud is a virtual storage space that exists on the Internet”. It is a storage space where people can place their digital resources such as software, applications and files.

History of Cloud Computing

Data is everywhere and this access to information has become one of the most impactful events in modern history.

The term “cloud computing” itself was coined in 1996 within a Compaq internal document.

The term “Cloud” was originally linked to the concept of distributed computing, which went mainstream at Apple-spawned General Magic in the early 1990s, with even earlier mentions in academic work before that.

In 1999, Salesforce.com started delivering of applications to users using a simple website. The applications were delivered to enterprises over the Internet, and this way the dream of computing sold as utility were true.

In 2002, Amazon started Amazon Web Services, providing services like storage, computation and even human intelligence. However, only starting with the launch of the Elastic Compute Cloud in 2006 a truly commercial service open to everybody existed.

In 2008, google released its beta version of Google App Engine.

In 2009, Microsoft launched Windows Azure, and companies like Oracle and HP have all started competiting in developing the new technologies.

Later various companies like oracle, IBM, etc., joined the game. And hence, cloud computing has seen the fastest adoption into the mainstream than any other technology in the domain.

About Cloud Computing

“Cloud Computing is an internet based new age computer technology, it can be defined as it is the delivery of different Computing services on internet -including servers, storage, databases, networking, software, analytics etc”.

Why Cloud Computing?

Again the question arises that why we need Cloud Computing , we can simply understand that cloud provides people to facilitate the access of applications and data from any place and everywhere if we are enough provided with the internet services / connection.

For example ,we access our photos the google photos by signing into our google account.

How the cloud computing works ?

From the above section ,we have known about the cloud and cloud computing , so mainly every service we get from the internet resources have a procedure about providing the services to the user, in the same way Cloud Computing is, Basically cloud is place to share information through satellite networks. Every cloud application has a host, and the hosting company is responsible for maintaining the massive data centers that provide the security, storage capacity and computing power needed to maintain all of the information users send to the cloud.

Client-Server Architecture

Now ,we learn about the architecture used by the Cloud Computing, bascially architecture is nothing but it is a structure of a system consisting of entities and their externally.

Cloud Computing uses the Architecture named Client-Server Architecture :

Cloud uses Client-Server Architecture because , a cloud have to able to provide resources or services for the users without any technical issues, so providing resources or services to the user can be done using the perfect architecuture ,so this can be made by the client- server architecture where client and server has specific functions to do.

What does client- server architecture mean?

Before acknowledging about the client-server architecture we should basically know exactly about the terms ‘client’ and ‘server’.

Client: It is a computer or system, Client computers provide an interface to allow a computer user to request to the server.

Server: It a computer or system ,it provides resources, data ,services and programs to the user as per the request of the client etc,

Client-Server Architecture is the computer network architecture in which the clients requests a resource and the server provides that resource.

A server may serve multiple clients at the same time while a client is in contact with only one server. Both the client and server usually communicate via a computer network but sometimes they may reside in the same system.

Cloud Computing Architecture

Cloud Computing Architecture is a combination of Service-Oriented architecture and event-driven architecture.

cloud computing architecture is divided into the following 2 parts:

In the simple technical terms we can define front end and back end as follows:

> Front End

The front end is used by the client. It contains client-side interfaces and applications that are required to access the cloud computing platforms. The front end includes web servers (including Chrome, Firefox, internet explorer, etc.),tablets, and mobile devices.

>Back End

The back end is used by the service provider. It manages all the resources that are required to provide cloud computing services. It includes a huge amount of data storage, security mechanism, virtual machines, deploying models, servers, traffic control mechanisms, etc.

Mainly there are 9 Components of Cloud Computing:

1. Client-Infrastructure
2. Application
3. Service
4. Runtime Cloud
5. Storage
6. Infrastructure
7. Management
8. Security
9. Internet

Cloud Services

Cloud Services are nothing but the services provided by the cloud on the different basis and aspects.

Generally, there are 3 main types of cloud computing :

1. Infrastructure as a Service (IaaS)

IaaS contains the basic building blocks for cloud IT. It typically provides access to networking features, computers (virtual or on dedicated hardware), and data storage space. IaaS gives you the highest level of flexibility and management control over your IT resources. It is most similar to the existing IT resources with which many IT departments and developers are familiar.

2.Platform as a Service(PaaS)

PaaS removes the need for you to manage underlying infrastructure (usually hardware and operating systems), and allows you to focus on the deployment and management of your applications. This helps you be more efficient as you don’t need to worry about resource procurement, capacity planning, software maintenance, patching, or any of the other undifferentiated heavy lifting involved in running your application.

3.Software as a Service(SaaS)

SaaS provides you with a complete product that is run and managed by the service provider. In most cases, people referring to SaaS are referring to end-user applications (such as web-based email). With a SaaS offering, you don’t have to think about how the service is maintained or how the underlying infrastructure is managed. You only need to think about how you will use that particular software.

Deployment Models

Public Cloud

Public clouds are owned and operated by a third-party cloud service providers , which deliver their computing resources like servers and storage over the Internet.

Private Cloud

A private cloud refers to cloud computing resources used exclusively by a single business or organisation. A private cloud can be physically located on the company’s on-site datacenter. Some companies also pay third-party service providers to host their private cloud. A private cloud is one in which the services and infrastructure are maintained on a private network.

Hybrid Cloud

Hybrid clouds combine public and private clouds, bound together by technology that allows data and applications to be shared between them. By allowing data and applications to move between private and public clouds, a hybrid cloud gives your business greater flexibility, more deployment options and helps optimise your existing infrastructure, security and compliance.

Advantages and Disadvantages of Cloud Computing

Advantages :

1. Back-up and restore data
2. Improved collaboration
3. Mobility
4. Excellent accessibility
5. Low maintenance cost
6. Unlimited Storage Capacity
7. Data Security
8. Services in pay-per-use

Disadvantages:

1. Internet connectivity
2. Vendor lock-in
3. Limted Control
4. Security
5. Downtime
6. Technical Issues

CIDR & Subnetting

CIDR: Classless Inter Domain Routing used for IP addressing and routing. It allocates IP addresses in more flexible manner by proving a new, more efficient way to allocate network addresses. With CIDR, one entry in the routing table entry represents a combination of networks existing in the forward path.

Subnetting: — It is process of stealing bits from the host part of an IP address in order to divide the larger network into smaller sub-networks called subnets.