Cloud Computing Models

Cloud Computing Models

There are three cloud models:

• Public Cloud: services offered over internet, no capex, pay for what you use
• Private Cloud: for one specific organization (internal use), complete control, hardware maintenance
• Hybrid Cloud: Combined use of Public and Private Clouds, more flexible

Cloud Computing Advantages

• High Availability
• Scalability
• Elasticity
• Agility
• Geo Distribution
• Disaster Recovery

CapEx vs OpEx

CapEx requires significant up-front financial costs, as well as ongoing maintenance and support expenditures. By contrast, OpEx is a consumption-based model.

Cloud service providers operate on a consumption-based model, which means that end users only pay for the resources that they use. Whatever they use is what they pay for. A consumption-based model has many benefits, including:

• No upfront costs.
• No need to purchase and manage costly infrastructure that users might not use to its fullest.
• The ability to pay for additional resources when they are needed.
• The ability to stop paying for resources that are no longer needed.

Cloud Service Models

• IaaS Infrastructure-as-a-Service

• PaaS Platform-as-a-Service

• SaaS Software-as-a-Service

The following diagram from Microsoft summarizes the three cloud service models.

Serverless

Serverless computing is similar to PaaS. Serverless architectures are highly scalable and event-driven, only using resources when a specific function or trigger occurs. Though the name says server less, there is a server running the applications, it is just that they are managed by the Cloud provider.