Cloud Computing Models

The cloud computing model affords the opportunity to deliver applications via the Internet, preclude the costs of owning and operating data centers, and leverage the work of software developers. Cloud computing and services are typically based on the ownership of the infrastructure (and to whom services are offered) and based on the general architecture visible to users (e.g., are they providing a platform for applications, or are they providing complete application software solutions as a service). Based on these services provided Cloud computing can be divided into three main models:
  • Software-as-a-Service (SaaS)
  • Infrastructure-as-a-Service (IaaS) and

  • Platform-as-a-Service (PaaS)
These three services make up the Cloud Computing Stack, with SaaS on top, PaaS in the middle, and IaaS on the bottom.
There are more than 3 service models that are widely in use today. More service models like ‘Data Analytics as a Service’ and ‘HPC/Grid as a Service’ are emerging as useful models. To select the right service model factors such as availability of suitable application software, need for development and testing environment, need for effective computing infrastructure control and management required distribution of data, services, and infrastructure, existence, and complexity of enterprise IT, infrastructure, and datacenter/warehouse are essential.
Cloud computing can also be categorized based on the deployment models. These classifications are based on the ability of an organization to manage business needs and secure assets
  1. Public cloud
  2. Private cloud
  3. Hybrid cloud


Examples of cloud computing

Many of us use cloud computing every day. And, that too without realizing it. When you ask Google for an answer, your computer or laptop isn't playing many parts in finding the answers you need.
Words involved in your queries are sent to one of hundreds of thousands of clustered PCs managed by Google. And, upon successful search, you get the answer. The entire process happens in a split second. When you do a Google search, the real work in finding your answers might be done by a computer/server sitting in California, Dublin, Tokyo, or New Zealand.
The Web-based email system is one of the common examples. Hotmail is one of the oldest which came along and carried email off into the cloud.
Preparing documents over the Net is a relatively newer example of cloud computing. Log on to a web-based service such as Google Documents, Google Forms, etc. and you can create a document, spreadsheet, presentation, or whatever you like using Web-based software. The document you produce is stored remotely, on a Web server, so you can access it from any Internet-connected computer, anywhere in the world, any time you like, and download when you want it.
When you use your computer for a web-based service like this, you are outsourcing your computing needs to companies like Google. Google invests in software development and keeps it up-to-date. They generate revenue by offering a host of paid services and through advertising as well.
Another example of Cloud is watching Movies and TV serials on Amazon Prime, Netflix, etc. Laptop – Video – Netflix

Types of cloud computing models

The different cloud computing models are:
  • Infrastructure as a Service (IaaS) – This means buying access to raw computing hardware over the Net, such as servers or storage. Web hosting like GoDaddy is a simple example of IaaS: you pay a monthly subscription or a per-megabyte/gigabyte fee to have a hosting company serve up files for your website from their servers.
  • Software as a Service (SaaS) – This means using a complete application running on someone else’s system. Some of the best examples in our day-to-day life are Web-based email and Google Documents.
  • Platform as a Service (PaaS) – In this module, you develop your web-based applications so they run on systems software and hardware of the cloud provider. Like an e-commerce website where the shopping cart, checkout, and payment mechanism are running on a merchant’s server. Big Basket, Flipkart, etc. are few examples of PaaS.
  • Cloud Services Brokerage (CSB) – This is an IT role and business model. Here the company adds value to one or more (public or private) cloud services on behalf of one or more consumers of that service.

What is Infrastructure-as-a-Service?

Infrastructure-as-a-Service (IaaS) refers to the elemental building blocks of computing which will be rented: physical or virtual servers, storage, and networking. This is attractive to companies that want to create applications from the very ground up and need to regulate nearly all the weather themselves, but it does require firms to have the technical skills to be able to orchestrate services at that level. In a research done by Oracle, nearly two-thirds of IaaS users said using online infrastructure makes it easier to innovate and helped cut their time to deploy new applications and services and there was a significant cut in ongoing maintenance costs. However, half also said that IaaS isn’t secure for critical data.

What is Platform-as-a-Service?

Platform-as-a-Service (PaaS) is the next layer up — as well as the underlying storage, networking, and virtual servers. This includes the tools and software required by developers to build applications on top that could include middleware, database management, operating systems, and development tools.

What is Software-as-a-Service?

Software-as-a-Service (SaaS) – Here the applications are provided as a service. This is the version of cloud computing that most people are used to on a day-to-day basis. The hardware and operating system are irrelevant to the end-user. He will access the service via a web browser or an application and it is often bought on a per-seat or per-user basis.
According to researchers IDC SaaS is — and will remain — the dominant cloud computing model in the medium term, accounting for two-thirds of all public cloud spending in 2017, which will only drop slightly to just under 60% in 2021. SaaS usage is mostly applications and system infrastructure software. The usage will be dominated by applications purchases, which will make up more than half of all public cloud spending. Customer relationship management (CRM) applications and enterprise resource management (ERM) applications will account for more than 60% of all cloud application spending through to 2021. The variety of applications delivered by SaaS is huge. It can be from Customer Relation Management such as Salesforce to Microsoft’s Office 365.

Types of cloud deployments

Based on an organization’s ability to manage and secure assets as well as business needs, cloud deployments are categorized into three types.
Public cloud: Public cloud is a SaaS service offered to users over the internet.
Private cloud: Private cloud is used by large organizations to build and manage their own data centers for specific business and IT needs/ operations.
Hybrid cloud: The combination of private and public cloud is called Hybrid cloud. This provides more flexibility to businesses while having control over critical operations and assets with improved flexibility and cost-efficiency.

What is Public Cloud?

Public cloud is a classic cloud computing model. In this model, the users can access a large pool of computing power over the internet (whether that is IaaS, PaaS, or SaaS). One of the significant benefits here is the ability to rapidly scale a service. The cloud computing suppliers have vast amounts of computing power, which they share out between a large number of customers — the ‘multi-tenant architecture. The huge scale of public cloud implies that they have enough spare capacity that they can easily cope up with the customer needing more resources. This is why it is often used for low-sensitive applications which demand a varying amount of resources.

What is a Private Cloud?

Private cloud allows organizations to benefit from some of the advantages of public cloud — but without the concerns about relinquishing control over data and services because it is tucked away behind the corporate firewall. Companies can control exactly where their data is being held and can build the infrastructure in a way they want — largely for IaaS or PaaS projects — to give developers access to a pool of computing power that scales on-demand without putting security at risk. This additional security comes at a cost, as few companies will have the scale of AWS, Microsoft, or Google. This means they will not be able to create the same economies of scale to get costs down. Still, for companies requiring additional security, a private cloud may be a useful stepping stone, helping them to understand cloud services or rebuild internal applications for the cloud, before shifting them into the public cloud.

What is Hybrid Cloud?

A hybrid cloud is where all users are in reality. It is a bit of this, a bit of that. Here the companies can store some data in the public cloud, few projects in the private cloud, manage multiple vendors, and usage of different levels of cloud usage. According to research by TechRepublic, the main reasons for choosing a hybrid cloud include disaster recovery planning and the desire to avoid hardware costs when expanding their existing data center.