AWS CLF-C02 — Domain 1: Cloud Concepts
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.
Instead of buying, owning, and maintaining physical data centers and servers, you can access technology services on an as-needed basis from a cloud provider like AWS.
Cloud computing eliminates the need to invest heavily in hardware upfront. Instead, you provision exactly the type and size of computing resources you need.
AWS defines six key advantages that are frequently tested on the exam:
| # | Advantage | Explanation |
|---|---|---|
| 1 | Trade CapEx for OpEx | Instead of investing in data centers before you know how you'll use them, you pay only when you consume resources. No upfront cost — pay for what you use. |
| 2 | Benefit from Massive Economies of Scale | Because AWS aggregates usage from thousands of customers, it achieves higher economies of scale, which translates into lower pay-as-you-go prices. |
| 3 | Stop Guessing Capacity | Eliminate guessing about infrastructure capacity needs. Scale up or down in minutes, not weeks. |
| 4 | Increase Speed & Agility | New IT resources are just a click away. Time to make those resources available drops from weeks to minutes. |
| 5 | Stop Spending Money Running Data Centers | Focus on projects that differentiate your business rather than on the undifferentiated heavy lifting of racking, stacking, and powering servers. |
| 6 | Go Global in Minutes | Deploy your application in multiple AWS Regions around the world with just a few clicks, providing low latency to customers globally. |
You WILL see questions asking you to identify the advantages of cloud computing. Memorize all six. The most commonly tested are "trade CapEx for OpEx," "stop guessing capacity," and "go global in minutes."
| Model | Description | Example |
|---|---|---|
| Public Cloud | Cloud resources owned and operated by a third-party provider, delivered over the Internet. Everything runs on the cloud provider's hardware. | AWS, Azure, GCP |
| Private Cloud (On-premises) | Cloud infrastructure provisioned for exclusive use by a single organization. May be managed internally or by a third party. Not exposed to the public. | Rackspace, VMware Cloud, OpenStack |
| Hybrid Cloud | Combination of public and private cloud. Keeps some servers on-premises and extends some capabilities to the cloud. Gives control over sensitive assets while leveraging cloud flexibility. | On-prem data + AWS for burst capacity |
If a question mentions keeping sensitive data on-premises while using cloud for other workloads, the answer is Hybrid Cloud.
| Model | What You Manage | What Provider Manages | AWS Examples |
|---|---|---|---|
| IaaS Infrastructure as a Service | OS, middleware, runtime, data, applications | Networking, storage, servers, virtualization | EC2, VPC, EBS |
| PaaS Platform as a Service | Data, applications | OS, middleware, runtime, networking, servers | Elastic Beanstalk, RDS, Lambda |
| SaaS Software as a Service | Nothing (just use it) | Everything | Rekognition, Gmail, Salesforce, Dropbox |
"Which model requires the customer to manage the operating system?" → IaaS. "Which model removes all management burden?" → SaaS.
us-east-1a, us-east-1b, us-east-1cRegions > Availability Zones > Edge Locations (in terms of infrastructure size). There are more Edge Locations than AZs, and more AZs than Regions.
"What should you consider when choosing an AWS Region?" → Compliance, latency/proximity, service availability, and pricing. This is a frequently asked question.
The Shared Responsibility Model defines who is responsible for what in the cloud. This is one of the most important concepts for the exam.
If a question asks "Who is responsible for patching the guest OS on EC2?" → Customer. "Who is responsible for the physical security of data centers?" → AWS. For managed services (like RDS, Lambda), AWS takes on MORE responsibility.
AWS has three fundamental pricing drivers:
| Pricing Driver | Description | Charged? |
|---|---|---|
| Compute | Pay for the compute time you consume (EC2, Lambda, etc.) | Yes — per hour or per second |
| Storage | Pay for the amount of data stored in the cloud (S3, EBS, etc.) | Yes — per GB per month |
| Data Transfer OUT | Pay for data transferred out of AWS to the Internet | Yes — per GB |
| Data Transfer IN | Data coming into AWS from the Internet | Free (in most cases) |
Data transfer IN to AWS is free. Data transfer OUT of AWS is charged. Data transfer between services in the same AZ using private IPs is free.
Remember: you are never charged for data transfer IN to AWS. Outbound data transfer is aggregated across services and charged per GB. This is a common distractor in pricing questions.