Public cloud
Services are offered over the public internet and available to anyone who wants to purchase them. Cloud resources, such as servers and storage, are owned and operated by a third-party cloud service provider, and delivered over the internet.
Private cloud
A private cloud consists of computing resources used exclusively by users from one business or organization. A private cloud can be physically located at your organization's on-site (on-premises) datacenter, or it can be hosted by a third-party service provider.
Hybrid cloud
A hybrid cloud is a computing environment that combines a public cloud and a private cloud by allowing data and applications to be shared between them.
Public cloud
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Private cloud
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Hybrid cloud
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No capital expenditures to scale up.
Applications can be quickly provisioned and deprovisioned.
Organizations pay only for what they use.
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Hardware must be purchased for start-up and maintenance.
Organizations have complete control over resources and security.
Organizations are responsible for hardware maintenance and updates.
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Provides the most flexibility.
Organizations determine where to run their applications.
Organizations control security, compliance, or legal requirements.
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cloud service models
IaaS: Infrastructure-as-a-Service
This cloud service model is the closest to managing physical servers;
a cloud provider will keep the hardware up-to-date,
but operating system maintenance and network configuration is up to you as the cloud tenant.
For example, Azure virtual machines are fully operational virtual compute devices running in Microsoft datacenters.
An advantage of this cloud service model is rapid deployment of new compute devices.
Setting up a new virtual machine is considerably faster than procuring, installing, and configuring a physical server.
The most flexible cloud service.
You configure and manage the hardware for your application.
PaaS: Platform-as-a-Service
This cloud service model is a managed hosting environment.
The cloud provider manages the virtual machines and networking resources,
and the cloud tenant deploys their applications into the managed hosting environment.
For example, Azure App Services provides a managed hosting environment where developers can upload their web applications,
without having to worry about the physical hardware and software requirements.
Focus on application development.
Platform management is handled by the cloud provider.
SaaS: Software-as-a-Service
In this cloud service model, the cloud provider manages all aspects of the application environment,
such as virtual machines, networking resources, data storage, and applications.
The cloud tenant only needs to provide their data to the application managed by the cloud provider.
For example, Microsoft Office 365 provides a fully working version of Microsoft Office that runs in the cloud.
All you need to do is create your content, and Office 365 takes care of everything else.
Pay-as-you-go pricing model.
Users pay for the software they use on a subscription model.
Cloud service model comparison