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Starts this lesson and continues through 35 more to the end of certification prep.
The SAA-C03 exam never asks you to define cloud computing. But every one of its four domains assumes you already think in the vocabulary this lesson sets up: elastic, on-demand, pay-as-you-go, managed, IaaS vs PaaS. And Domain 4 in particular is built on the economic argument AWS makes for the cloud — trade fixed expense for variable expense — so you need that argument in AWS's own words.
There is also a correction to make up front. The fundamentals video this module was planned from talks about "the five criteria of cloud computing". Those five are NIST's essential characteristics, not an AWS list. AWS's own overview whitepaper lists six advantages, which are a different thing. Both are below, with their sources, so you never mix them up.
From the SAA-C03 exam guide home page, fetched 2026-09-25, the target candidate description, verbatim and in full:
"The target candidate should have at least 1 year of hands-on experience designing cloud solutions that use AWS services."
⚠️ That is the whole description on the HTML guide page I fetched. It carries no "recommended AWS knowledge" or "recommended general IT knowledge" list. If you have seen such a list elsewhere, it did not come from this page — read the guide home page yourself before relying on one.
So this module anchors instead on the "Knowledge of" lines in the domain pages that name fundamentals directly. Fetched 2026-09-25:
| Task | "Knowledge of" line (verbatim) | Lesson |
|---|---|---|
| 1.1 | "AWS global infrastructure (for example, Availability Zones, AWS Regions)" | 2 |
| 1.1 | "The AWS shared responsibility model" | 4 |
| 1.2 | "Determining network segmentation strategies (for example, using public subnets and private subnets)" (a skill line) | 5 |
| 1.3 | "Encrypting data at rest (for example, AWS KMS)" / "Encrypting data in transit (for example, AWS Certificate Manager [ACM] using TLS)" (skill lines) | 5 |
| 2.2 | "AWS global infrastructure (for example, Availability Zones, AWS Regions, Amazon Route 53)" | 2, 3 |
| 3.2 | "Distributed computing concepts supported by AWS global infrastructure and edge services" | 2 |
| 3.4 | "How to design network architecture (for example, subnet tiers, routing, IP addressing)" | 5 |
| 4.2 | "Instance types, families, and sizes (for example, memory optimized, compute optimized, virtualization)" | 5 |
| 4.4 | "Network services with appropriate use cases (for example, DNS)" | 5 |
Global infrastructure appears in four of the four domains. That is why it gets a lesson of its own.
From What is cloud computing? in the Overview of Amazon Web Services whitepaper, fetched 2026-09-25:
"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."
And the ownership line, which is the seed of the Shared Responsibility Model in lesson 4:
"A cloud services platform such as Amazon Web Services owns and maintains the network-connected hardware required for these application services, while you provision and use what you need via a web application."
Three phrases carry the definition: on-demand, via the internet, pay-as-you-go. Hold them.
The industry reference definition is NIST Special Publication 800-145. The NIST landing page carries only the abstract; the five characteristics are in the PDF, section 2, which I retrieved on 2026-09-25. The definition, verbatim:
"Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model is composed of five essential characteristics, three service models, and four deployment models."
| # | Characteristic | NIST's words |
|---|---|---|
| 1 | On-demand self-service | "A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider." |
| 2 | Broad network access | "Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations)." |
| 3 | Resource pooling | "The provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand." |
| 4 | Rapid elasticity | "Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand." |
| 5 | Measured service | "Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service…" |
Two details in the full text are worth having:
| NIST characteristic | Where it shows up in AWS's definition |
|---|---|
| On-demand self-service | "on-demand delivery", "you provision and use what you need" |
| Broad network access | "via the internet" |
| Resource pooling | "owns and maintains the network-connected hardware" |
| Rapid elasticity | "access as many resources as you need, almost instantly" |
| Measured service | "pay-as-you-go pricing", "only pay for what you use" |
That mapping is mine, not AWS's — AWS's page never cites NIST. But every AWS phrase has a NIST twin, and knowing both vocabularies means a question phrased either way reads the same to you.
NIST's three service models, abridged but verbatim (SP 800-145 §2):
And AWS's own phrasing, from Types of Cloud Computing, fetched 2026-09-25:
| Model | AWS, verbatim |
|---|---|
| IaaS | "contains the basic building blocks for cloud IT and typically provides access to networking features, computers (virtual or on dedicated hardware), and data storage space." |
| PaaS | "remove the need for organizations to manage the underlying infrastructure (usually hardware and operating systems)…" |
| SaaS | "provide you with software applications that are run and managed by the vendor." |
⚠️ The single discriminator is the operating system. In NIST's IaaS text the consumer "has control over operating systems"; in PaaS the consumer "does not manage or control… operating systems". Keep that — lesson 4 turns it into the Shared Responsibility Model, where the guest OS is exactly the line that moves between EC2 and RDS.
AWS's Types of cloud computing page in the overview whitepaper, fetched 2026-09-25, lists three deployment models:
| AWS model | AWS, verbatim |
|---|---|
| Cloud | "A cloud-based application is fully deployed in the cloud and all parts of the application run in the cloud." |
| Private cloud (on-premises) | "The deployment of resources on-premises, using virtualization and resource management tools, is sometimes called the private cloud. On-premises deployment doesn't provide many of the benefits of cloud computing but it is sometimes sought for its ability to provide dedicated resources." |
| Hybrid | "A hybrid deployment is a way to connect infrastructure and applications between cloud-based resources and existing resources that are not located in the cloud." |
NIST lists four: private, community, public, hybrid. Two differences matter:
And NIST's hybrid — "two or more distinct cloud infrastructures… bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting…)" — is broader than AWS's, which is framed as "between the cloud and existing on-premises infrastructure".
For this exam, hybrid is the one that matters. Task 4.2 names "Hybrid compute options (for example, AWS Outposts)" and Task 4.1 names "Hybrid storage options (for example, AWS DataSync, AWS Transfer Family, AWS Storage Gateway)" (domain 4 page, fetched 2026-09-25).
From Six advantages of cloud computing, fetched 2026-09-25. Headlines verbatim, with the sentence that makes each one examinable:
| # | Advantage | The load-bearing sentence |
|---|---|---|
| 1 | Trade fixed expense for variable expense | "you can pay only when you consume computing resources, and pay only for how much you consume." |
| 2 | Benefit from massive economies of scale | "Because usage from hundreds of thousands of customers is aggregated in the cloud, providers such as AWS can achieve higher economies of scale, which translates into lower pay as-you-go prices." |
| 3 | Stop guessing capacity | "When you make a capacity decision prior to deploying an application, you often end up either sitting on expensive idle resources or dealing with limited capacity." |
| 4 | Increase speed and agility | "you reduce the time to make those resources available to your developers from weeks to just minutes." |
| 5 | Stop spending money running and maintaining data centers | "rather than on the heavy lifting of racking, stacking, and powering servers." |
| 6 | Go global in minutes | "Easily deploy your application in multiple regions around the world with just a few clicks… lower latency and a better experience for your customers at minimal cost." |
⚠️ Six advantages ≠ five characteristics. The characteristics describe what cloud is. The advantages describe why you'd buy it. An exam distractor that says "one of the five characteristics of cloud computing is economies of scale" is mixing the two lists.
"Stop guessing capacity" is the one that recurs in design questions: any answer that has you pre-provisioning for peak on EC2 when the workload is spiky is fighting advantage 3, and the elastic answer (Auto Scaling, serverless, on-demand capacity) is usually the right one.
From the overview whitepaper introduction (publication date shown on the page: June 02, 2026), fetched 2026-09-25:
"Amazon Web Services offers a broad set of global cloud-based products including compute, storage, databases, analytics, networking, mobile, developer tools, management tools, IoT, security, and enterprise applications: on-demand, available in seconds, with pay-as-you-go pricing. … over 200 AWS services are available."
And the history line: "In 2006, Amazon Web Services (AWS) began offering IT infrastructure services to businesses as web services—now commonly known as cloud computing."
For exam purposes you don't need 200 services. The In-Scope AWS Services page is the list that matters, and it says of itself: "This list is non-exhaustive and is subject to change."
The useful mental model is the one NIST gives you: every AWS service sits somewhere on the IaaS → PaaS → SaaS spectrum, and the further right it sits, the more AWS runs for you. That position predicts two things the exam cares about: