Public VS Private VS Hybrid Cloud

Public Cloud

With a public cloud, all hardware, software, and other supporting infrastructure is owned and managed by the cloud provider. You share the same computing hardware, storage, and network devices with other organizations or cloud tenants. Most often you're subscribing to a virtualized environment that separates your compute from other subscribers.

• Utility model: Public clouds generally offer the lowest cost. Public clouds usually deliver a pay-as-you-go model where you have to pay by the hour for the resources that you use. This is indeed an economical way to opt for if you’re tearing down and spinning up the development servers on a daily basis.
• No particular contracts required: Besides the utility model, you’re simply paying by the hour and if you wish to shut down the server after using it for 2 hours, there will be no contract that requires your ongoing use of the server.
• Hardware is shared: Since the public cloud is by definition a multi-tenant environment, your server is supposed to share the same hardware, network devices and storage as all the other tenants who are there in the cloud.
• Hardware performance control not required: In the public cloud, you won’t be able to choose the hardware, storage performance or cache. Your virtual server will be placed on whichever hardware and network the cloud provider designates for you.

Private Cloud

A private cloud consists of computing resources used exclusively by one business or organization. The private cloud can be physically located at your organization’s on-site datacenter, or it can be hosted by a third-party service provider. But in a private cloud, the services and infrastructure are always maintained on a private network and the hardware and software are dedicated solely to your organization.

• Security: Since the private clouds are dedicated to a specific organization, the data storage, the hardware and the network can be tailored in such a manner that it assures high levels of security that can never be accessed by any other client of the same center.
• Personalize-able: Storage performance, network performance and hardware performance can be easily specified and customized through the private cloud computing system.
• Compliance: PCI, Sarbanes-Oxley and HIPAA compliance can’t be delivered through a public cloud computing system and must be on a private cloud due to the strictest of privacy concerns.

Hybrid Cloud

Hybrid clouds combine on-premise infrastructure, or private clouds, with public clouds so organizations can enjoy the advantages of both. In a hybrid cloud environment, data and applications can move between private and public clouds for greater flexibility and more deployment options.

• Control: your organization can maintain a private infrastructure for sensitive assets.
• Flexibility: you can take advantage of additional resources in the public cloud when you need them.
• Cost effective: with the ability to scale to the public cloud, you pay for extra computing power only when needed.
• Ease of migration: transitioning to the cloud doesn’t have to be overwhelming because you can migrate gradually, moving in phases over time.

Resources

“Private / Public / Hybrid.” MDL Technology, www.mdltechnology.com/private-public-hybrid/.

“Public Cloud vs Private Cloud.” HCL Technologies, www.hcltech.com/technology-qa/public-cloud-vs-private-cloud.