The types of cloud computing can be classified based on two model perspectives. One is based on the type of access and the other is based on the type of capabilities. If you classify clouds based on type of capabilities or deployment method, different types are public clouds, private clouds, community clouds and hybrid clouds.
Any subscriber with an Internet connection can access a public cloud. This is the traditional method of cloud computing. Some services are made freely available, whereas some others are offered as pay-per-use model. All customers share the same infrastructure in case of public clouds. Though it is shared commonly, resources are properly encrypted to ensure security. Amazon Web Services and Google Apps are examples of public cloud.
Only members of a particular group or organization can access a private cloud. Cloud computing model is deployed on private networks in case of private clouds, thus offering better data security and greater control over data. The software or virtual hardware would be in organization’s hosts itself. This is usually referred to as on-premise private cloud. This type of private cloud offers the organization the complete control over applications. Private cloud can also be hosted externally with a cloud provider. Organizations that do not prefer public clouds can go for this externally hosted private cloud model.
This cloud is a combination of two or more clouds. The clouds could be public, private or community. Moreover, if physical hardware and virtual cloud instances are together used to get a common service, then that also could be called as a hybrid cloud.
Types of Cloud Computing – Community Cloud
One or more organizations with similar cloud requirements can access a community cloud. Different cloud requirements could be security, jurisdiction, compliance etc. Though this type of cloud is comparatively expensive to implement as the cost is shared only among few users, it provides more security and privacy to the services enjoyed. The resources of the cloud could be kept in-house or on public cloud based on the requirements of the organizations.
Different Types of Cloud Computing Based on Capabilities
- Infrastructure as a Service (IaaS)
- Software as a Service (SaaS)
- Platform as a Service (PaaS)
- Security as a Service (SECaaS)
- Storage as a Service (STaaS)
Out of the above specified cloud models, the most popular ones are IaaS, SaaS and PaaS. In the IaaS model, as the name suggests, the whole infrastructure is made available as a service over the network. Different hardware, software etc are pooled and made available to handle loads. Different servers, network equipment, storage systems etc are included in the cloud. Three examples of Infrastructure as a Service (IaaS) are Microsoft Azure, Amazon Web Services, and Google Compute Engine.
Types of cloud computing: in SaaS model, different applications are offered as service. On the cloud service provider’s end, only a single instance of a particular service would be running and many different users around the globe would be using the same service. As a single instance is used, it is easy for the provider to host and maintain it, whereas customer need not have to pay for the server or software license. Thus, both provider and customer are benefiting from cloud computing concept. Companies like Microsoft, Google, SalesForce etc offer SaaS.
Types of cloud computing: in PaaS, a layer of software or hardware is encapsulated and provided as a service. So, the consumer can build higher levels of applications or services above this. Usually in this model, providers offer a predefined combination of OS and applications like LAMP, which offers Linux, Apache, MySql and PHP. Google App Engine, Azure Service Platform etc are examples of PaaS.