Cloud Computing: Service Models (IaaS, PaaS, SaaS), Multitenancy, and Governance

Cloud computing is the on-demand delivery of compute power, database storage, applications, and other IT resources through a cloud services platform via the internet with pay-as-you-go pricing.

This guide details cloud service models (IaaS, PaaS, SaaS, FaaS), hypervisor virtualization security, the Shared Responsibility Model, and FinOps cloud cost management.

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1. Quick-Reference: Shared Responsibility Model

+-----------------------------------------------------------------------------------------+
|                               SHARED RESPONSIBILITY MATRIX                              |
+-----------------------------------------------------------------------------------------+
| Layer                  | IaaS (EC2 / Compute)              | PaaS / Serverless (Lambda) |
+------------------------+-----------------------------------+----------------------------+
| Customer Data & IAM    | CUSTOMER RESPONSIBILITY           | CUSTOMER RESPONSIBILITY    |
| Application Code & API | CUSTOMER RESPONSIBILITY           | CUSTOMER RESPONSIBILITY    |
| OS Patching & Runtime  | CUSTOMER RESPONSIBILITY           | CLOUD PROVIDER MANAGED     |
| Hypervisor & Compute   | CLOUD PROVIDER MANAGED            | CLOUD PROVIDER MANAGED     |
| Physical Datacenter    | CLOUD PROVIDER MANAGED            | CLOUD PROVIDER MANAGED     |
+-----------------------------------------------------------------------------------------+