Cloud is a buzz word in the era of technology. It has solved the problem that we had in legacy platform. In legacy platform before building a solution for end user, the organization first need to requisite necessary hardware. Once the hardware arrives they need to make sure the environment is ready before entering in the developing phase. All these process are time consuming as well as it cost too much money for hardware and its maintenance. Another problem that organization frequently faced was at the time of scaling. Scale up and down is one kind of flexibility that every organization must have. Cloud platform solves all these issues. Cloud gives the ability to scale out seamlessly. If you have an app idea just choose the appropriate cloud platform you are ready to go. You don’t have to wait for the hardware. Instead of buying new servers, you simply drag your Instance slider to get more machines. This saves a lot of money and time.
We have three cloud delivery model which are discussed below:
Software as a Service (also known as SaaS) is a software delivery model that fall under cloud architecture pattern which uses a highly multi-tenant architecture. Generally, third party vendor hosts an application on your behalf and make it available to customers on a subscription basis. In SaaS basically what happens is that instead of installing software on your local computer, the software actually resides in computer up in the cloud. Somebody else has the server running the application, where you simply connect somehow with a web browser or a thin interface
This model is getting popular in the industry for its lowered operational and capital expenses for enterprise information technology services. The provider typically charge for a certain level of service – $X/month for N projects and Y users. The provider may also provide access to the software free of charge or through a pay-as-you-go model.
In most cases, SaaS application does not require additional downloads/installation on your local machine, instead you can enjoy the service from within your browser, in rare extreme the browser might require some additional small plugins. Since all the processing and logic are running and serving directly from cloud, it makes the update process simple and automated. Service provider can update and patches on their end and all the connected user can get the updated version right away.
In essence, SaaS customers don’t have to concern themselves with their hardware, facilities, or operating systems as they would in a traditional model—they simply pay a fee for the service.
Example: Office 365 which provides an online version of MS Office Suite (Office Web Apps) along with SharePoint Server, Exchange Server and Lync Server. Google’s services such as GMail, Calendar, Maps and Drive
- The software is provided ‘on-demand’
- Software is managed from a central location
- No additional hardware cost.
- No upfront commitments
- Accessible from any location
- Cross device compatibility
- Update process easier and automated
Where SaaS is not suitable:
- If your applications require extremely fast processing of real time data then SaaS is not suitable because of the time it takes to transfer data from the cloud to your pc or vice versa.
- If organization deals with too much sophisticated data and legislation or other regulation does not permit data being hosted externally.
- If organization already has an existing on-premise solution that fulfills all of the organization’s needs then SaaS is not a good choice.
PaaS or Platform as a Service is a cloud computing solution which run applications without the hassle of maintaining the hardware and software infrastructure at your organization. It is designed to help organization particularly developers that’s runs on top of IaaS. Using this model organization can develop new applications or services in the cloud that does not depend on a specific platform. In essence, In this model you usually lease virtualized servers and associated services for running existing applications and you got control over the operating system.
One comparison between SaaS vs. PaaS has to do with what aspects must be managed by users, rather than providers. With PaaS, vendors still manage runtime, middleware, O/S, virtualization, servers, storage, and networking, but users manage applications and data.
- Microsoft’s Azure, Google’s app Engine, Salesforce, Heroku, OpenShift are very well familiar for PaaS.
Infrastructure as a Service aka IaaS is a category of cloud computing that provides one of the three fundamental service models of cloud computing alongside Platform as a Service (PaaS) and Software as a Service (SaaS). The IaaS provider takes responsibility for the hardware and performs all the maintenance to ensure the servers run correctly. Its also referred as “Hardware as a Service (HaaS)”.
Below is the snapshot of Windows Azure IaaS service:
The above image is a visual representation of the cloud delivery models from the end users perspective. In sum, SaaS is a model where end user can acquire services based on subscription plan. S/He does not have any control over applications/data or any other things. The subscriber can only acquire service on demand. In PaaS model user gets little bit control over their applications and data. S/He does not have any privileged on runtime, middleware, operating system etc part. Those parts still managed by the vendors. In IaaS, you will get more control on infrastructure part.