Public cloud is a cloud infrastructure provisioned for use by the general public, individuals or businesses. Essentially, third-party public cloud providers lease servers within a virtual environment, which is accessible over Internet. Users can then access these servers by purchasing public cloud services such as cloud servers, data storage, and other cloud-related services. Ideal for SMEs businesses or businesses that have fluctuating demands. Public cloud is a low cost cloud computing solution. It delivers a pay-as-you-go model, and no need for hardware.
Private cloud is a model of cloud computing that provides a dedicated cloud environment to a single organization. Private cloud can be operated internally by an in-house IT team, behind that organization’s firewall, so an organization has more control of its compute resources. Private cloud gives more security and is mainly used by enterprises, so it is also considered a type of enterprise cloud. Private cloud could be on-premises or hosted in a shared data center or even a public cloud provider’s data center Compared to public cloud, private cloud is very costly.
Hybrid cloud is a cloud computing model that combines one or more public cloud and private cloud environments through a secure connection such as a VPN connection or leased line, which allows sharing of data and applications between the different cloud environments. When applications running on private cloud encounter spikes in usage, they can automatically “burst” to the public cloud environment for extra on-demand capacity. This is called “cloud bursting”. As the extra demand will be on the public cloud, there is no need to worry about provisioning hardware in advance to meet peak demand. There are two methods to connect public cloud and private cloud: VPN and point to point dedicated connections.
|Public Cloud||Private Cloud||Hybrid Cloud|
|Physical Server Provisioning||No||Yes||Yes|
|Need for Maintenance Personnel||No||Yes||Yes|
|Elastic & Scalable||Yes||No||Yes|
|Flexibility of Management||No||Yes||Yes|
|Storage Space||Unlimited||Limited||Unlimited, through cloud bursting|
|Example Scenarios||Web, Email, CRM, Collaboration, HR||ERP, R&D, BI, Supply Chain Management, Analytics||Customer Service Call Center, Remote Sites, Bank|