AWS Compute and Storage Services 3 — Questions and Answers
Question 1: An application needs to process jobs from a queue and scale in/out based on queue depth. Which EC2 feature best supports this pattern?
- EC2 Auto Scaling with a custom CloudWatch metric based on SQS queue depth (Correct answer)
- EC2 Reserved Instances with scheduled scaling
- EC2 Spot Fleet with a fixed capacity
- EC2 Dedicated Hosts with manual scaling
Correct answer: EC2 Auto Scaling with a custom CloudWatch metric based on SQS queue depth
EC2 Auto Scaling can use custom CloudWatch metrics—such as SQS queue depth—as scaling triggers to dynamically adjust capacity.
Question 2: Which S3 storage class is designed for data that is accessed less than once per month and requires millisecond retrieval?
- S3 Glacier Flexible Retrieval
- S3 Standard-IA
- S3 Glacier Instant Retrieval (Correct answer)
- S3 One Zone-IA
Correct answer: S3 Glacier Instant Retrieval
S3 Glacier Instant Retrieval is designed for rarely accessed archive data (once per quarter) but provides millisecond retrieval times.
Question 3: A company wants to run a stateful containerized application on AWS without managing servers. Which service should they use?
- Amazon ECS with EC2 launch type
- AWS Fargate (Correct answer)
- Amazon EC2 with Docker installed manually
- AWS Lambda
Correct answer: AWS Fargate
AWS Fargate is a serverless compute engine for containers that removes the need to provision or manage EC2 instances.
Question 4: What is the maximum size of a single object that can be uploaded to S3 using a single PUT operation?
- 5 TB
- 100 GB
- 5 GB (Correct answer)
- 50 GB
Correct answer: 5 GB
A single S3 PUT operation supports objects up to 5 GB; use Multipart Upload for objects larger than 5 GB (up to 5 TB total).
Question 5: Which EC2 purchasing option provides the largest discount compared to On-Demand pricing but can be interrupted by AWS with a two-minute notice?
- Reserved Instances
- Savings Plans
- Spot Instances (Correct answer)
- Dedicated Instances
Correct answer: Spot Instances
EC2 Spot Instances offer up to 90% discount over On-Demand pricing but can be reclaimed by AWS with a two-minute interruption notice.
Question 6: An EBS volume is attached to an EC2 instance that is stopped. What happens to the data on the EBS volume?
- Data is deleted immediately when the instance stops
- Data persists until the volume is explicitly deleted (Correct answer)
- Data is moved to S3 automatically
- Data is encrypted and archived to Glacier
Correct answer: Data persists until the volume is explicitly deleted
EBS volumes are persistent storage; data remains intact when an instance is stopped and is only lost if the volume itself is deleted.
Question 7: Which AWS service allows you to run code in response to events without provisioning servers, billed per 1ms of execution time?
- Amazon ECS
- AWS Fargate
- AWS Lambda (Correct answer)
- Amazon EC2 Auto Scaling
Correct answer: AWS Lambda
AWS Lambda is a serverless compute service that runs code in response to events and charges based on the number of requests and duration in 1ms increments.
AWS Compute and Storage Services 3
An application needs to process jobs from a queue and scale in/out based on queue depth.
Which EC2 feature best supports this pattern?