Before we dive in Cloud Computing Service models lets first understand the basic terminologies of Cloud Computing and its Services offered.
What is Cloud Computing Service?
Firstly, Cloud is a term for the collection of servers at the data centre accessed via the internet. Similarly, Cloud Computing Services covers a wide range of options from storage, database, software, analytics, servers, processing and intelligence over the internet. Moreover, It makes the organization only pay for the services they use and avoid the cost of owning and maintaining their own data centres. The Benefits of Cloud Computing is tremendously large. Firstly, it is cost-effective. Secondly, it provides the security of the data on the cloud servers. In addition, it is reliable and Flexible. Thirdly and most importantly, it is location Independent and also provides Disaster recovery. Moreover, it provides a Scale-up and Scale-down facility. In conclusion, it maximizes productivity and efficiency ensuring the application is always accessible.
Based on NIST (National Institute of Standards and Technology) definition on Cloud Computing it consists of three different service models
Infrastructure as a Service (IaaS)
In Infrastructure as a Service (IaaS), a third-party provider provides the user resources like server, virtual machine, hardware, software, storage and networking, on a pay-as-you-go basis. Moreover, Infrastructure as a Service (IaaS) provides user access computing services without developing and maintaining its own IT infrastructure. In conclusion, the user runs its application and platform on the IT infrastructure provided by third-party.
Examples of Infrastructure as a Service providers:
- Amazon EC2 ( Elastic Cloud Computing)
- Google Compute Engine
- Microsoft Azure IaaS
- IBM Cloud
- Apache CloudStack
Platform as a Service (PaaS)
Platform as a Service (PaaS) is like an application service. In Platform as a Service (PaaS), the third-party user provides the hardware (Required IT Infrastructure) as well as the software which the user can use to develop, manage and delivery applications. As a result, the third-party provider takes care of the security, Operating System, Backups and Softwares at the server end.
Examples of Platform as a Service providers:
- Amazon Web Services – Elastic Beanstalk
- Salesforce
- IBM – Bluemix
- Google – app engine
- VMware – Pivotal CF
Software as a Service (SaaS)
In Software as a Service (SaaS), the user purchases software application from third-party providers on a subscription basis. Also, the user does not have the software application stored on the localhost/personal computer beside the application resides in the servers of third-party provider accessed via the internet. Above all, It provides accessibility from anywhere, anytime from any device. In conclusion, the third-party provider takes care of all the hardware, software updates and security patches.
Examples of Software as a Service providers:
- Oracle
- SAP
- Cobweb
- Adobe
- Microsoft
Comparing Cloud Computing Service Models
| Infrastructure as a Service (IaaS) | Platform as a Service (SaaS) | Software as a Service (SaaS) |
|---|---|---|
| The User manages the application and platform, while the third-party provider takes care of the IT infrastructure required. | In this case, the User develops the application on the framework provided by the third-party provider. | Generally, the user has to utilize the application provided by the third-party provider. |
| Applications, Operating System, Runtime, Middleware, etc., are all configured by the User, Hence provides more control. | The operating system, Runtime, Middleware, etc., are controlled by third-party, User has the control only over the application. Hence, provides less control. | Applications, Operating System, Runtime, Middleware, etc., are all controlled by the third-party provider. For this reason, the user has the least control in this model |
| As a result, its cost is high as compared to other models. | In this case, the cost of the model is moderate compared to others. | The cost is the least compared to other models. Moreover, it provides monthly based subscriptions. |
| For these reasons, System Managers mostly prefer this model. It is also known as Cloud Infrastructure Service. | For these reasons, Developers and Deployers mostly prefer this model. | For these reasons, Business users mostly prefer this model. |
