The term "cloud" is analogous to "Internet". The term "Cloud Computing" is based on cloud drawing used in the past to represent telephone networks and later to depict the Internet.
Cloud Computing is a virtual space where a large pool of systems is connected in private or public networks, to provide dynamically scalable infrastructure for application, data and file storage. With the advent of this technology, the cost of computation, application hosting, content storage and delivery is reduced significantly. Cloud computing is a practical approach to experience direct cost benefits and it has the potential to transform a data center from a capital intensive set up to a variable priced environment.
Moreover, it is Internet-based computing where virtual shared servers provide software, infrastructure, platform, devices, and other resources and hosting to customers on a pay as you use basis. All information that a digitized system has to offer is provided as a service in the cloud computing model. Users can access these services available on the "Internet Cloud" without having any previous knowledge on managing the resources involved. Thus, users can concentrate more on their core business processes rather than spending time and gaining knowledge on resources needed to manage their business processes. Cloud computing customers do not own the physical infrastructure; rather they rent the usage from third party provider. This helps them to avoid huge capital investments. They consume resources as a service and pay only for resources that they use. Most cloud computing infrastructures consist of services delivered through shared resources. This increases efficiency as servers are not unnecessarily left idle, which can reduce costs significantly while increasing the speed of application development.
Cloud Computing Architecture
Cloud computing architecture consists of two components "the front end" and "the back end". The front end of the cloud computing system comprises the client's device(or it may be a computer network) and some applications are needed for accessing the cloud computing system. The back end refers to the cloud itself which may encompass various computer machines, data storage systems, and servers. The Group of these clouds makes a whole cloud computing system. The whole system is administered via a central server that is also used for monitoring clients demand and traffic ensuring the smooth functioning of the system. A special type of software called "middleware" is used to allow computers that are connected to the network to communicate with each other. Cloud computing systems also must have a copy of all its client's data to restore the service which may arise due to a device breakdown. Making copies of data is called redundancy and cloud computing service providers provide data redundancy.
Cloud Computing Services
Cloud providers offer services that can be grouped into three categories
1. Software as a service(SaaS) : In this model, a complete application is offered to the customer, as a service on demand. A single instance of the service runs on the cloud and multiple end users are serviced. On the customers' side, there is no need for upfront investment in servers or software licenses, while for the provider, the costs are lowered, since only a single application needs to be hosted and maintained. Today SaaS is offered by companies such as Google, Salesforce, Microsoft, Zoho etc.
2. Platform as a Service(PaaS) : Here, a layer of software, or development environment is encapsulated and offered as a service, upon which other higher levels of service can be built. The customer has the freedom to build his own applications, which run on the provider's infrastructure. To meet manageability and scalability requirements of the applications, PaaS providers offer a predefined combination of OS and application servers, such as LAMP platform(Linux, Apache, MySQL and PHP), restricted J2EE, Ruby etc. Google's App Engine, Force.com etc. are some of the popular PaaS examples.
3. Infrastructure as a Service(IaaS): IaaS provides basic storage and computing capabilities as standardized services over the network. Servers, storage systems, networking equipment, data center space etc. are pooled and made available to handle workloads. The customer would typically deploy his own software on the infrastructure. Some common examples are Amazon, GoGrid, 3 Tera, etc.
Cloud Computing Types
There are three different deployment models of cloud computing :
1. Public Cloud : Public clouds are owned and operated by third parties; they deliver superior economies of scale to customers, as the infrastructure costs are spread among a mix of users, giving each individual client an attractive low cost, " Pay as you go" model. All customers share the same infrastructure pool with limited configuration, security protections, and availability variances. These are managed and supported by the cloud provider. One of the advantages of a public cloud is that they may be larger than an enterprises cloud, thus providing the ability to scale seamlessly, on demand.
2. Private Cloud : Private cloud is a computing model that offers a proprietary environment dedicated and accessible to a single business entity. As with other types of cloud computing environments, private cloud provides extended, virtualized computing resources via physical components stored on-premises or at a vendor's datacenter.
3. Hybrid Cloud : Hybrid clouds combine both public and private cloud models. With a Hybrid Cloud, service providers can utilize 3rd party Cloud Providers in a full or partial manner thus increasing the flexibility of computing. The Hybrid cloud environment is capable of providing on demand, extremely provisioned scale. The ability to augment a private cloud with the resources of a public cloud can be used to manage any unexpected surges in workload.
Other cloud computing types are multi cloud and community cloud.
Cloud Computing Benefits
Enterprises would need to align their applications, so as to exploit the architecture models that Cloud Computing Offers.
Some of the typical benefits are listed below:
1. Reduced Cost : There are a number of reasons to attribute Cloud Technology with lower costs. The billing model is pay as per usage; the infrastructure is not purchased thus lowering maintenance. Initial expense and recurring expenses are much lower than traditional computing.
2. Increased Storage : With the massive Infrastructure that is offered by Cloud providers today, storage and maintenance of large volumes of data is a reality. Sudden workload spikes are also managed effectively and efficiently, since the cloud can be scaled dynamically.
3. Flexibility : This is an extremely important characteristic. With enterprises having to adapt, even more rapidly, to changing business conditions, speed to deliver is critical. Cloud computing stresses on getting applications to market very quickly, by using the most appropriate building blocks necessary for deployment.
4. Backup and Recovery : Data stored in the cloud helps us to auto backup and recover instantly. As we change the data the system changes itself.
5. Mobility : Cloud computing allows us to access our data via smartphones and devices, which is a great way to ensure that nobody is left out of updated data. Resources in the cloud can be accessed 24/7.
Cloud Computing Disadvantages
Despite having many advantages following are some disadvantages of using cloud computing:
1. Risk of data confidentiality : There is always a risk that user data can be accessed by other people. To prevent it there must be high level of security such that only authorized users can access their data.
2. Internet Connection Dependency : Since the cloud is the Internet so whatever we save, gets saved on the Internet. To access our data the internet connection must be of higher bandwidth. Lower bandwidth may cause slow downloading or no downloading of data.
3. Level of Security : Although cloud service providers implement the best security standards and industry certifications, storing data and important files on external service providers always opens up risks. Any discussion involving data must address security and privacy, especially when it comes to managing sensitive data. We must not forget what happened at Code Space and the hacking of their AWS EC2 console, which led to data deletion and the eventual shutdown of the company. Their dependance on remote cloud based infrastructure meant taking on the risks of outsourcing everything.
4. Downtime : Downtime is often cited as one of the biggest disadvantages of cloud computing. Since cloud computing systems are internet based, service outages are always an unfortunate possibility and can occur for any reason.
5. Cost Concerns : Adopting cloud computing solutions on a small scale and for short term projects can be perceived as being expensive. However, the most significant cloud computing benefit is in terms of IT cost savings. Pay as you go cloud services can provide more flexibility and lower hardware costs, but the overall price tag could end up being higher than you expected. Until you are sure of what will work best for you, it's good idea to experiment with a variety of offerings.
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