A public cloud is a platform that uses the standard cloud computing model to make resources -- such as virtual machines, applications or storage -- available to users remotely. Public cloud services may be free or offered through a variety of subscription or on-demand pricing schemes, including a pay-per-usage model.
The main benefits of the public cloud are as follows:
- a reduced need for organizations to invest in and maintain their own onpremises IT resources;
- scalability to meet workload and user demands; and
- fewer wasted resources because customers only pay for what they use.
How does the public cloud work?
Public cloud is an alternative application development approach to traditional onpremises IT architectures. In the basic public cloud computing model, a third-party provider hosts scalable, on-demand IT resources and delivers them to users over a network connection, either over the public internet or a dedicated network.
The public cloud model encompasses many different technologies, capabilities and features. At its core, however, a public cloud consists of the following key characteristics (more detail at 8 key characteristics of cloud computing):
- on-demand computing and self-service provisioning;
- resource pooling;
- scalability and rapid elasticity;
- pay-per use pricing;
- measured service;
- resiliency and availability;
- security; and
- broad network access.
The public cloud provider supplies the infrastructure needed to host and deploy workloads in the cloud. It also offers tools and services to help customers manage cloud applications, such as data storage, security and monitoring.
General cloud providers offer broad availability and integration options and are desirable for multipurpose cloud needs. Niche providers offer more customization.
Migration
Myriad factors drive businesses to migrate from on-premises facilities to the public cloud. For example, some organizations require support for more diverse workload types that data centers can't provide. Cost considerations, less overhead maintenance and redundancy are other common reasons.
After choosing a provider, the IT team must select a cloud migration method to move data into the provider's cloud. Offline migration requires IT teams to copy local data onto a portable device and physically transfer that hardware to the cloud provider.
Online data migration occurs via network connection over the public internet or a cloud provider's networking service.
When the amount of data to transfer is significant, offline migration is typically faster and less expensive. Online migration is a good fit for organizations that won't move high volumes of data.
Organizations also onboard existing on-premises applications into the cloud, and there are a few approaches to consider. A lift-and-shift method moves the application to the cloud as is, without any redesign. This approach is fast, but is prone to complications -- the application may not perform properly within cloud architecture and may cost more than if it remained on premises. Alternatively, IT teams can refactor on-premises applications ahead of the migration. Refactoring takes more time and planning, but this method ensures that the application will function effectively in the cloud. Another option is to rebuild entirely as a cloud-native application.
Whichever strategy you choose, there are a range of cloud-native and third-party migration tools to help you manage the move to the public cloud.
