AWS Certified Cloud Practitioner: Cloud Concepts Concepts
Importance ★★★★☆ · 24% (estimate)
Overview
This chapter covers why companies use the cloud and how they plan the move. You learn the benefits of the AWS Cloud, the six pillars of the AWS Well-Architected Framework, the common migration strategies, and the six perspectives of the AWS Cloud Adoption Framework (AWS CAF). Most questions describe a business situation and ask which benefit, pillar, strategy, or perspective it matches.
The main benefits of the cloud are easy to remember as short phrases. You trade fixed expense for variable expense, so you pay only for what you use. You benefit from economies of scale, stop guessing capacity, increase speed and agility, stop spending money running data centers, and go global in minutes. Elasticity means resources grow and shrink with demand, often automatically.
The Well-Architected Framework has six pillars: operational excellence, security, reliability, performance efficiency, cost optimization, and sustainability. Reliability is about recovering from failure, and running across multiple Availability Zones is a key way to stay available. Loose coupling, such as using a queue between parts of a system, keeps one failure from stopping everything.
Migration strategies describe what happens to each application. Rehost is lift and shift, replatform makes a few changes such as moving to a managed database, and refactor redesigns the application. Repurchase switches to a new product, retire turns an application off, retain keeps it where it is, and relocate moves VMware workloads as they are. AWS CAF groups planning advice into the Business, People, Governance, Platform, Security, and Operations perspectives.
Key concepts
Fixed vs variable expense
Instead of buying servers up front (fixed), you pay each month only for the resources you use (variable).
Memory tipPay as you go = variable expense
Elasticity
Adding resources when demand rises and removing them when demand falls, often automatically.
Memory tipGrow and shrink with demand
Well-Architected pillars
Operational excellence, security, reliability, performance efficiency, cost optimization, and sustainability.
Memory tipScalability is not a pillar
Migration strategies
Rehost, replatform, refactor, repurchase, retire, retain, and relocate describe what happens to each application.
Memory tipLift and shift = rehost
AWS CAF perspectives
Business, People, Governance, Platform, Security, and Operations, each giving advice for one area of cloud adoption.
Memory tipSkills and culture = People
Rightsizing
Matching instance types and sizes to what a workload actually uses so you do not pay for idle capacity.
Memory tipLow CPU all day = too big
Often tested
- Not guessing how many servers you need = stop guessing capacity.
- Environmental impact is the Sustainability pillar.
- Moving to Amazon RDS without redesign = replatform.
- Switching to a SaaS product = repurchase.
- Run across at least two Availability Zones for high availability.
Easy to confuse: Migration strategies at a glance
| Strategy | What happens | Example |
|---|---|---|
| Rehost | Move as is | Lift and shift to EC2 |
| Replatform | A few cloud changes | Self-managed database to Amazon RDS |
| Refactor | Redesign the application | Old app rewritten as serverless services |
| Repurchase | Switch to a new product | Move to a SaaS product |
| Relocate | Move at the virtualization level | VMware to VMware Cloud on AWS |
| Retain / Retire | Keep it / turn it off | Recently upgraded app / unused app |
3 sample questions
Verified practice questions from this unit.
Question 1. A small company wants to stop buying servers up front and instead pay each month only for the computing it actually uses. Which benefit of the AWS Cloud does this describe?
- ① Trade fixed expense for variable expense
- ② Increase speed and agility
- ③ Go global in minutes
- ④ Benefit from massive economies of scale
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Answer: ① Trade fixed expense for variable expense
Key point: Pay as you go = fixed expense becomes variable
With the cloud you trade fixed expense for variable expense. Instead of paying a large amount up front for servers and data centers, you pay only for the resources you use.
Wrong choices
- Benefit from massive economies of scale: This is about AWS's large size lowering prices, not about paying only for what you use.
- Increase speed and agility: This is about getting resources faster, not about how you pay.
- Go global in minutes: This is about reaching users in other parts of the world quickly.
Question 2. A garden supply store gets very busy every spring. In the past it had to predict months ahead how many servers it would need. Which AWS Cloud benefit removes this problem?
- ① Benefit from massive economies of scale
- ② Go global in minutes
- ③ Stop guessing capacity
- ④ Stop spending money running and maintaining data centers
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Answer: ③ Stop guessing capacity
Key point: Scale with demand = stop guessing capacity
In the cloud you can add or remove resources as demand changes, so you stop guessing capacity. You no longer pay for idle servers or run short when traffic grows.
Wrong choices
- Go global in minutes: This is about reaching new countries quickly, not about sizing for demand.
- Benefit from massive economies of scale: This is about lower prices from AWS's size.
- Stop spending money running and maintaining data centers: This is about letting AWS handle the building, power, and hardware.
Question 3. An online shop's web servers are added automatically when many shoppers visit and removed automatically when traffic drops. Which cloud concept is this?
- ① High availability
- ② Data residency
- ③ Elasticity
- ④ Durability
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Answer: ③ Elasticity
Key point: Grow and shrink automatically = elasticity
Elasticity is the ability to add resources when demand rises and remove them when demand falls, often automatically. You pay only for what you use at each moment.
Wrong choices
- High availability: High availability means a system keeps running when a part fails.
- Durability: Durability means stored data is not lost.
- Data residency: Data residency is about which country or Region data is kept in.
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