A Survey on Cloud Computing

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International Journal on Advanced Computer Theory and Engineering (IJACTE)

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ISSN (Print): 2319-2526, Volume -3, Issue -4, 2014 42

1S. Ravi Kumar, ²K. Chandra Sekharaiah, ³Y.K. Sundara Krishna

1Research Scholar, Krishna University, Machilipatnam, A.P., India.

2 Professor, School of Information Technology, Jawaharlal Nehru Technology University, Hyderabad, India.

3 Professor, Dept of Computer Science, Krishna University, Machilipatnam, A.P., India Email: [email protected], [email protected]

Abstract: In this paper, we present cloud characteristics,

services, deployment models, technologies, implementations & providers, virtualization, security and privacy issues in quite a variegation and multifarious setting.

Keywords: Cloud Computing, Virtualization, Leverage, Security.

I. INTRODUCTION

Cloud Computing is the new name from mid of 90’s as “on-demand infrastructure”. In 1995, it was known as “shared web hosting” and had the features multi- tenant, automated provisioning and easy-to-use interface. In 1997, dedicated hosting web access both managed and unmanaged. This automated computing had servers with full administrative access. In 1998, became available web hosting, improved by having partial infrastructure demand, resource size flexibility.

In 2000, automated computing became closer to be known as cloud.

From 2012, onwards Cloud Computing has attracted a wider audience to develop and startup needs became easier, more scalable and flexible services.

Cloud Computing is anything that provides hosted services over the internet. These services are sharing to the end users. The main uses of cloud are data storage, process and management services on the internet rather than having local servers. The service provider has to look up all the issues related to the cloud. The end-user doesn’t require any server to maintain, simply requesting the services from the cloud and pay for using it. Fig.1 depicts the Cloud Computing capabilities.

II. CHARACTERISTICS OF CLOUD

According to National Institute of Standard Technology (NIST, U.S.Department of Commerce), cloud has five essential characteristics such as on demand self service, broad network access, resource

pooling, rapid elasticity, measured service. They are briefed as follows.

2.1 On demand self service: Resources can provide in a fully automated fashion, without requiring human interaction at the service provider. The ultimate goal is a resource available “instantly” whenever customer requires it.

2.2 Broad network access: Capabilities are available over the network can be accessed by variety of end user terminal devices, desktop machines, thin clients on mobile devices.

2.3 Resource pooling: The service provider is expected to construct physical infrastructure such that all resources are located at one or more common pools. Customers are not able to specify their physical location of the resources that are assigned to them from the pool.

2.4 Rapid elasticity: Users should be able to allocate and release the capacity as they required by them. Its importance is that elasticity is a two way application needs to be allocating new resources as well as release them when no longer need them.

2.5 Measured service: Generally resources should be billed on fine granularity (hours/days, weeks/months/years) in the cloud as they are used, resources using appropriate units (GB/TB or Mbps/Gbps etc).

III. SERVICES OF CLOUD COMPUTING

Eleven cloud services are: Storage-as-a-Service, Database-as-a-Service, Information-as-a-Service, Process-as-a-Service, Software-as-a-Service, Platform-as-a-Service, Integration-as-a-Service, Security-as-a-Service, Management/ Governance-as- a-Service, Testing-as-a-Service, Infrastructure-as-a- Service. They are briefed as follows and depicted in Fig.2.

3.1 Storage-as-a-Service (SaaS): It is ability to leverage storage that physically exists at remote site.

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3.2 Database-as-a-Service (DaaS): It provides the ability to leverage the services of a remotely hosted database, sharing it other users.

3.3 Information-as-a-Service (InfaaS): It is ability to consume any type of information, remotely hosted, through a well defined interface such as an API.

3.4 Process-as-a-Service (PraaS): It is remote resource that can bind many resources together, such as services and data.

3.5 Software-as-a-Service (SaaS): SaaS provides software application to the users. The users don’t pay owning the software rather than pay per using it.

3.6 Platform-as-a-Service (PaaS): PaaS provides users with development platforms to develop and execute software.

3.7 Integration-as-a-Service (IntaaS): The ability to deliver a complete integration stacks from the cloud, including interfacing with applications, semantic mediation, flow control, integration design, and so on.

3.8 Security-as-a-Service (SeaaS): It’s ability to deliver core security services remotely over the internet.

3.9 Management / Governance-as-a-Service (MaaS and GaaS): It is the ability to demand any service that provides to manage one or more cloud services.

3.10 Testing-as-a-Service (TaaS): The ability to test local cloud or cloud delivery systems using testing software and services that are remotely hosted.

3.11 Infrastructure-as-a-Service (IaaS): IaaS provides computing, storage, networking infrastructure.

Figure 2 Types of Cloud Computing services

IV. CLOUD DEPLOYMENT MODELS

Cloud has four deployment models. These are public cloud, private cloud, community cloud, hybrid cloud.

They are briefed as follows.

4.1 Public cloud: The public cloud can utilize for general public, anyone can use it.

4.2 Private cloud: Private cloud is meant solely for an organization.

4.3 Community cloud: Community is for special community composed of several organizations with shared concerns.

4.4 Hybrid cloud: Hybrid cloud is a combination of the clouds. (I.e. public, private or community clouds)

V. CLOUD COMPUTING TECHNOLOGIES

Six technologies related to cloud computing are Web Services, XML (Extensible Markup Language), SOAP (Simple object Access Protocol), WSDL (Web Services Description Language), UDDI (Universal Description Discovery and Integration) and WS- Security (Web Service Security). They are briefed as follows.

5.1 Web Services: Two applications are written in different languages and executed in different operating systems, no matter in which languages are written or in which operating system is running.

Ex: In Internet, we don’t know how to implement a process for running on the web.

5.2 XML (Extensible Markup Language): It is a Meta language based on labels. It is very structured and allows in different applications or systems to communicate between them. It is said that the name is extensible, means that it allows defining new labels very easily.

5.3 SOAP (Simple Object Access Protocol): It is a protocol that defines how two objects of different processes can exchange information through XML messages.

5.4 WSDL (Web Services Description Language):

Based on XML and it is the public interface in the world of web services. It describes all the services that exist in one location and the way to interact with them.

5.5 UDDI (Universal Description Discovery and Integration): It is a catalogue of all web services that exist in Internet; it was an industrial initiative but now a day it’s not really used. It is written in XML.

5.6 WS-Security (Web Service Security): It is an extension to SOAP to apply security to web services.

Figure 1: Cloud Computing Capabilities

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VI. PROVIDERS AND IMPLEMENTATIONS

Google cloud providers can be implemented according to the user requirements, which can also be used daily through internet from all over the world. A snapshot of different implementations of google cloud providers is depicted in Fig. 3.

6.1 Google Apps: It is office suite service that everybody can use through webserver.

6.2 Gmail: It is one of the useful services utilized all over the world. It was released in the 2007 and 194 billion people are being utilized now.

6.3 Google Docs: This service is to write and edit documents in real time; it is possible to share among other users.

6.4 Google Calendar: The google calendar services are compatible with standards.

6.5 Google groups: It offers services to discuss within the groups and other groups.

6.6 Google talk: The service is useful for instant message and video chat.

6.7 Google sites: This service is useful for creating and editing web pages and intranets.

Figure3 Different implementations of Google Cloud providers

VII. VIRTUALIZATION

Virtualization is a technique that it is partitioning or dividing the resources into single server to multiple Virtual machines. It provides more utilization, rapid development, energy saving, improved maintenance capability, isolation, and encapsulation. It enables application migration from one server to another while running, without downtime, providing flexible workload management.

7.1 Virtual Machine (VM): Virtual Machine is a software machine which implements that executes like a physical machine. It provides a complete system platform that supports the operating system.

Fig.4 depicts different layers of VM management tools and technologies.

Figure4 Different layers of VM management tools and technologies.

The Virtual Machine has a six phases: create, resume, suspend, save, migrate and destroy. Multiple VMs can run simultaneously in the same physical system. Each VM can have different OS and a Virtual Machine Monitor (VMM) used to control and manages on a single physical system. The VMM is referred as a Hypervisor.

7.1.2 Virtualization Platforms: Virtualization technology has been developed for utilizing computing capacity.

Virtualization methods can be classified into two categories. These are Full Virtualization and Paravirtualization. Comparisons of full virtualization and paravirtualization as shown in Fig.5.

Full Virtualization emulates the entire hardware environment by utilizing hardware virtualization support, binary code translation or binary code rewriting and thus the guest OS does not need to modify its kernel. It is also important for running non open source operating system such as windows, because it is too difficult to modify windows kernel without source code.

Paravirtualization requires the guest OS kernel to be modified to become aware of the hypervisor. Because it need not emulate the entire hardware environment, paravirtualization can attain better performance than full virtualization.

Figure 5 Comparisons of Full Virtualization and Paravirtualization

7.1.3 Virtual Infrastructure Manager (VIM): VIM is responsible for the efficient management of a virtual infrastructure, by providing the basic functionality of deploying, controlling and monitoring of VMs in a distributed pool of resources.

7.1.4 Cloud Infrastructure Manager (CIM): A CIM is a web based solution focused on deploying and

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managing services (deploying, monitoring and maintaining VMs) on top of IaaS clouds.

8. Security and Privacy Issues in Cloud Computing There are numerous security issues in cloud computing in many technologies like networks, databases, operating systems, virtualization, load balancing, transaction management, resource scheduling, concurrency control and memory management. Therefore security issues for many of these systems and technologies are applicable to cloud computing.

In cloud computing providing security is not an easy task for cloud providers, the cloud service model or models are affected by these security problems. First of all clouds are on internet, so all security problems related to internet including attacks and hackers may happen. Some of the issues related to the cloud are,

 Lack of employees screening and poor hiring practices--some cloud providers may not perform background screening of their employees or providers.

 Lack of customers background checks— cloud providers do not check their customer’s background, and almost anyone can open the account with a valid credit card and Email-id.

If there is no proper checking for opening account it leads to any malicious activities without being identified.

 Due to lack of security in the cloud, the educated people will not get valid information, which is a weak point in information security.

It is true in any type of organization; however in the cloud it has bigger impact, because there are more number of people interact with the cloud like cloud providers, third party providers, suppliers, organizational customers and end users.

 It is clear that security issues play an important role in cloud computing acceptance. Putting the data, running the software on someone else hard disk doubting too many issues. Well known security issues such as data lose, phishing pose serious threats to organization’s data and software. Moreover, the multi- tenancy model and pooled computing

resources in cloud computing has introduced new security challenges that require novel techniques to tackle with those issues. For Example: hackers can use cloud to organize botnet (running remotely on a collection of machines) as a cloud often provides more reliable infrastructure services at a relatively cheaper price for them to attack.

 Data confidentiality in cloud computing is a correlated user authentication, protecting user account from the hackers is an instance of larger problem of controlling and access to objects, including memory, devices, software etc.

IX. CONCLUSIONS

Cloud computing technology is increasingly used and it gives promising approaches for the government, public and private sectors of education, medicine, defence etc. It is a moot question whether the merits of cloud computing technologies outweigh the demerits or vice. There is a scope for implementing the cloud technologies in the academics.

REFERENCES

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[2] Michael Miller, “Cloud Computing-Web Based Applications That Change the Way You Work and Collaborate Online”, ISBN:

9780768686227 Publisher: Que.

[3] Nick Antonopoulos, Lee Gillam Editor,

“Cloud Computing Principles, Systems and Applications”, Computer Communications and Networks.

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