Cloud Computing

Abstract:

In today’s world where everyone is going mobile and people want to carry small devices with all applications on different platforms are creating complications .A new technology ie Cloud computing offers solution to this problem .A cloud computing platform dynamically provisions, configures, reconfigures, and deprovisions servers as needed. Servers in the cloud can be physical machines or virtual machines Cloud computing also describes applications that are extended to be accessible through the Internet. These cloud applications use large data centers and powerful servers that host Web applications and Web services. Anyone with a suitable Internet connection and a standard browser can access a cloud application. Cloud computing infrastructures can allow enterprises to achieve more efficient use of their IT hardware and software investments. They do this by breaking down the physical barriers inherent in isolated systems, and automating the management of the group of systems as a single entity. Cloud computing is an example of an ultimately virtualized system, and a natural evolution for data centers that employ automated systems management, workload balancing, and virtualization technologies.

Architecture:

Cloud architecture, the systems architecture of the software systems involved in the delivery of cloud computing, comprises hardware and software designed by a cloud architect who typically works for a cloud integrator. It typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services.
This closely resembles the Unix philosophy of having multiple programs doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.
Cloud architecture extends to the client, where web browsers and/or software applications access cloud applications.
Cloud storage architecture is loosely coupled, where metadata operations are centralized enabling the data nodes to scale into the hundreds, each independently delivering data to applications or users

Benefits:
• Virtual relocation: allows the cloud management system to dynamically relocate virtual machines (guest operating systems) in a matter of seconds with zero downtime.
• Instant archiving: allows the cloud to take a unused server offline with no ill affect. Later that same virtual machine can be restored and brought online in a matter of seconds.
• Instant rebalancing: allows the cloud to move over utilized virtual machines to physical machines that have unused resources (memory, CPU, disk).
• Instant deployment: allows the cloud to bring a virtual server online in a matter of seconds. Additional configurations or middleware and application provisioning may require additional time depending on the implementation.
A SAN based storage architecture must be used for some of these software virtualization benefits to be realized.
This dynamic allocation of resource and the large number of active pilots enable cloud resources to be extremely efficient. A non virtualized environment may well be able to handle less than half the number of projects of a virtualized cloud.

Infrastructure as a Service (IaaS)
Infrastructure as a Service (IaaS) is the delivery of computer infrastructure as a service. Rather than purchasing servers, software, data center space or network equipment, clients instead buy those resources as a fully outsourced service.

Example: Amazon Web Services(AWS)
1. AWS’ Elastic Comput Cloud (EC2)
2. Simple Storage Service (S3)

Platform as a Service(PAAS)

The PaaS model makes all of the facilities required to support the complete life cycle of building and delivering web applications and services entirely available from the Internet — with no software downloads or installation for developers, IT managers or end-users.

Example: Google App Engine (GAE)

Software as a Service (SAAS)

Software as a Service is a model of software deployment where an application is hosted as a service provided to customers across the Internet. By eliminating the need to install and run the application on the customer’s own computer.

Example: Google Docs, Salesforce