There are three models of Cloud Computing based on the security and offerings by the cloud computing providers. These are:
In a Public Cloud, the service provider creates resources such as portals, applications and storage which are available to the general public (anyone) on Internet. Anyone having internet access can use the Cloud Services. It can be free or charge some nominal fee based on the usage.
Public clouds contain different types of applications offered by different vendors or cloud service providers. All these applications are hosted on cloud which are away from different client locations and provide much cheaper services to all the customers.
As, Public Cloud is open for all the general public on internet and is accessible by everyone there is significant security threats involved and there are chances of losing key information to other people. That’s the main reason; companies or individuals never chose Public cloud for running sensitive application.
Few examples of public clouds are Amazon Elastic Compute Cloud, IBM’s Blue Cloud, Sun Cloud and Google App Engine etc.
In Private Cloud, the usage is limited to a particular client. This provides them with maximum control over data, enhanced security and quality of service. The Private Cloud exists within the firewall of the organization.
The organization owns everything starting from the Infrastructure to Applications running on the Private Cloud. The Private Cloud service is provided to limited number of user groups or people within an organization.
As the security is managed by the organization itself and it is shared only within the organization, the risk involved in Private Cloud is very less and there is no fear of losing key information to outside people. Moreover the costs are also reduced as it is highly utilized within the organization.
The Hybrid Cloud is a combination of both Private and Public Clouds. These are used for collaborating Private Clouds with the Public Clouds in order to cater different types of users within an organization. It is used to provide on-demand business based on the security needs of the users.
In Hybrid Clouds, different types of applications are distributed across both Public and Private Clouds. Suppose an organization uses Private Cloud for business critical applications to be used only by its senior management. At the same time, it uses Public Cloud for other non-critical applications to be used by all of its employees where there is no significant security risk involved.
Hybrid Cloud enables to utilize the server and storage resources properly by using both the Private and Public Clouds on need basis. Due to this, peak workload can be handled easily using this.