need of cloud computing and virtualization

Cloud Computing

What is Cloud?

The term Cloud refers to a Network or Internet. In other words, we can say that Cloud is something, which is present at remote location. Cloud can provide services over network, i.e., on public networks or on private networks, i.e., WAN, LAN or VPN. Applications such as e-mail, web conferencing, customer relationship management (CRM),all run in cloud.

What is cloud computing?

Cloud computing is a model for enabling convenient, on-demand network. access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned. and released with minimal management effort or service provider interaction.

historical development of cloud computing:

•  It was a gradual evolution that started in the 1950s with mainframe computing.
• After some time, around 1970, the concept of virtual machines (VMs) was created.
• In the 1990s, telecommunications companies started offering virtualized private cloud.
• Salesforce.com in 1999, which pioneered the concept of delivering enterprise applications via a simple website.
• The next development was Amazon Web Services in 2002, which provided a suite of cloud-based services including storage, computation and even human intelligence through the Amazon Mechanical Turk.
• Another big milestone came in 2009, as Web 2.0 hit its stride, and Google and others started to offer browser-based enterprise applications, though services such as Google Apps.

deployment model of cloud computing:

 it has four model show in below

 PUBLIC CLOUD The Public Cloud allows systems and services to be easily accessible to the general public. Public cloud may be less secure because of its openness, e.g., e-mail.

 PRIVATE CLOUD The Private Cloud allows systems and services to be accessible within an organization. It offers increased security because of its private nature.

 COMMUNITY CLOUD The Community Cloud allows systems and services to be accessible by group of organizations.

 HYBRID CLOUD The Hybrid Cloud is mixture of public and private cloud. However, the critical activities are performed using private cloud while the  non-critical activities are performed using public cloud.

Services provided by cloud computing:

service model:

Software as a Service (SaaS) is a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over a network, typically the Internet.

Platform as a Service (PaaS) is a paradigm for delivering operating systems and associated services over the Internet without downloads or installation.

Infrastructure as a Service (IaaS) involves outsourcing the equipment used to support operations, including storage, hardware, servers and networking components.

benifits of cloud computing:

1. Flexibility.
2. Disaster recovery.
3. Automatic software updates.
4. Capital-expenditure Free.
5. Increased collaboration.
6. Work from anywhere.
7. Document control.
8. Security.
9. Reliability.
10. scalebility.

challenges for cloud computing:

1. Security and Privacy

The main challenge to cloud computing is how it addresses the security and privacy concerns of businesses thinking of adopting it. The fact that the valuable enterprise data will reside outside the corporate firewall raises serious concerns. Hacking and various attacks to cloud infrastructure would affect multiple clients even if only one site is attacked. These risks can be mitigated by using security applications, encrypted file systems, data loss software, and buying security hardware to track unusual behavior across servers.

 2. Service Delivery and Billing

It is difficult to assess the costs involved due to the on-demand nature of the services. Budgeting and assessment of the cost will be very difficult unless the provider has some good and comparable benchmarks to offer. The service-level agreements (SLAs) of the provider are not adequate to guarantee the availability and scalability. Businesses will be reluctant to switch to cloud without a strong service quality guarantee.

3. Interoperability and Portability

Businesses should have the leverage of migrating in and out of the cloud and switching providers whenever they want, and there should be no lock-in period. Cloud computing services should have the capability to integrate smoothly with the on-premise IT.

4. Reliability and Availability

Cloud providers still lack round-the-clock service; this results in frequent outages. It is important to monitor the service being provided using internal or third-party tools. It is vital to have plans to supervise usage, SLAs, performance, robustness, and business dependency of these services.

5. Performance and Bandwidth Cost

Businesses can save money on hardware but they have to spend more for the bandwidth. This can be a low cost for smaller applications but can be significantly high for the data-intensive applications. Delivering intensive and complex data over the network requires sufficient bandwidth. Because of this, many businesses are waiting for a reduced cost before switching to the cloud.

cloud computing technologies:

1.Virtualization

Virtualization is a technique, which allows to share single physical instance of an application or resource among multiple organizations or tenants (customers). It does so by assigning a logical name to a physical resource and providing a pointer to that physical resource when demanded.

2. Service-Oriented Architecture(SOA)

Service-Oriented Architecture helps to use applications as a service for other applications regardless the type of vendor, product or technology. Therefore, it is possible to exchange of data between applications of different vendors without additional programming or making changes to services

3.Utility Computing

Utility computing is based on Pay per Use model. It offers computational resources on demand as a metered service. Cloud computing, grid computing, and managed IT services are based on the concept of Utility computing.

4.Grid Computing

Grid Computing refers to distributed computing in which a group of computers from multiple locations are connected with each other to achieve common objective. These computer resources are heterogeneous and geographically dispersed.



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