L2. Cloud Computing Models and the AWS Value Proposition

Six Advantages of Cloud Computing (AWS Framework)

AWS defines six advantages of cloud computing that the Cloud Practitioner exam tests:

1. Trade capital expense for variable expense: pay only for what you consume instead of investing in datacenters upfront
2. Benefit from massive economies of scale: AWS aggregates usage from hundreds of thousands of customers, achieving lower costs
3. Stop guessing capacity: scale up or down based on actual demand; no over-provisioning
4. Increase speed and agility: provision resources in minutes, not weeks
5. Stop spending money running and maintaining datacenters: focus on what differentiates your business
6. Go global in minutes: deploy in multiple AWS Regions with minimal effort

Cloud Deployment Models

Public cloud: all resources run on a shared public cloud infrastructure (AWS). No hardware ownership. Private cloud (on-premises cloud): resources run exclusively on your own infrastructure; you manage hardware. AWS Outposts brings AWS services to your datacenter. Hybrid cloud: combines on-premises (private) with AWS (public). Common for gradual migrations or regulated data scenarios. Multi-cloud: using more than one cloud provider simultaneously (e.g., AWS + Azure).

Cloud Service Models

IaaS (Infrastructure as a Service): AWS manages the physical layer; you manage OS and above. Example: Amazon EC2. PaaS (Platform as a Service): AWS manages infrastructure AND OS/runtime; you manage application and data. Example: AWS Elastic Beanstalk, Amazon RDS. SaaS (Software as a Service): AWS manages everything; you consume the application. Example: Amazon WorkMail, AWS Managed Services.

AWS Global vs. Regional Services

Not all AWS services are Regional:

• Global: IAM, Route 53, CloudFront, AWS Organizations (no Region selection needed)
• Regional: EC2, S3 (global namespace but data resides in a Region), RDS, Lambda

Well-Architected Framework (Overview)

The AWS Well-Architected Framework provides guidance for building secure, high-performing, resilient cloud systems. It has six pillars (covered in Lesson 4). Exam tip: The six advantages of cloud computing are a common source of Cloud Practitioner exam questions. Memorize them as stated by AWS, not in your own words.