Global infrastructure: CLF-C02 study notes and practice questions
What to know about Global infrastructure for the CLF-C02 exam, from the Cloud Technology and Services domain (34% of the exam guide), then 2 free questions to test it. Part of the CLF-C02 study guide.
Global infrastructure questions ask how AWS is built physically and which piece gives you high availability, low latency or data residency.
The pieces
Piece
What it is
Use it for
Region
A separate geographic area (such as US East (N. Virginia) or Europe (Frankfurt)) with its own set of Availability Zones
Data residency, being close to users, disaster recovery across Regions
Availability Zone (AZ)
One or more data centers with independent power, cooling and networking, connected to the other AZs in the Region by low-latency links
High availability: run across at least two AZs
Edge location
A site in many cities worldwide used by CloudFront, Route 53 and Global Accelerator
Low latency for content delivery and DNS
Local Zone
AWS compute and storage placed in a large city, linked to a parent Region
Single-digit millisecond latency for users in that city
Wavelength Zone
AWS infrastructure inside telecom 5G networks
Ultra-low latency mobile applications
AWS Outposts
AWS racks installed in your own data center
Running AWS services on premises
Choosing a Region
Four factors: compliance and data residency (laws may require data to stay in a country), proximity to users (lower latency), service availability (not every service is in every Region), and pricing (prices vary by Region).
Key facts
Data stays in the Region you choose unless you move it.
Regions have multiple AZs (new Regions launch with at least three), and AZs in a Region are physically separate (meaningful distances apart) to avoid shared failures.
Some services are global (IAM, Route 53, CloudFront); most are regional.
How to choose
“Survive the failure of one data center”: deploy across multiple Availability Zones.
“Survive a disaster affecting a whole area”: deploy across multiple Regions.
“Store data only in Canada”: choose a Canadian Region.
“Deliver videos with low latency worldwide”: CloudFront using edge locations.
Common traps
Availability Zone vs Region. AZs give high availability within a Region; Regions give geographic separation.
Edge locations run your servers. They don’t; they cache content and serve DNS (Local Zones are the option for running compute nearby).
B. Wrong: One extra copy helps only the students near that Region, and the company must keep two buckets in step. It does not cache content close to students across the world.
C. Wrong: Direct Connect is a dedicated network link between a company's data center and AWS. Students' home networks cannot use it, and it does not cache videos.
D. Wrong: More servers in the same Region still sit far from students in Asia and South America. They add compute but do not place cached copies near viewers.
Explanation
CloudFront delivers content through edge locations around the world, caching copies near viewers and fetching from the origin when needed. The S3 bucket stays the source of the content. The other options either add capacity in one Region or are network links that do not cache content for public viewers.
A video-editing company's artists work in a city about 1,500 km from the nearest AWS Region.
They need EC2 workstation instances that respond with low latency, and the company wants AWS to run the physical infrastructure, not its own hardware.
Which option should it choose?
Choose one answer.
AA. A second Availability Zone in the nearest AWS Region, for resilience
BB. AWS Global Accelerator in front of instances in the nearest AWS Region
CC. Amazon CloudFront edge locations to host the workstation instances
DD. AWS Local Zones in the city, which run EC2 and EBS close to large population centers
Show the answer and explanation
Answer: D
A. Wrong: Availability Zones inside the same Region are still far from the artists. A second zone improves resilience, but it does not reduce latency for the workstations.
B. Wrong: Global Accelerator routes traffic over the AWS network to your endpoints, which speeds up the path. The workstation instances still run in the distant Region, so the latency goal is missed. Learn more: AWS Global Accelerator components (opens in a new tab)
C. Wrong: CloudFront edge locations cache content for delivery. They do not run EC2 instances, so they cannot host the workstations.
D. Right: Correct. Local Zones place compute and storage close to large population centers, and each one stays linked to a parent Region. AWS operates the infrastructure, and the artists get the low-latency instances they need. Learn more: What is AWS Local Zones? (opens in a new tab)
Explanation
Local Zones place compute, storage and database resources close to large population centers, while staying linked to a parent Region. A second Availability Zone or Global Accelerator leaves the workstations in the distant Region, and CloudFront edge locations cache content rather than running EC2 instances.
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