AWS Module 6.7 introduction to lambda

Question 1

What is AWS Lambda and how does it differ from EC2?

Answer 1

AWS Lambda is a serverless compute service that runs code in response to events.

EC2:
* You manage servers

Lambda:
* No server management
* Runs code automatically when triggered

Question 2

What does “serverless” actually mean in Lambda?

Answer 2

You don’t manage infrastructure — AWS handles provisioning, scaling, and maintenance.

Question 3

What is an event-driven architecture in Lambda?

Answer 3

Code runs only when triggered by an event (e.g., file upload, API call).

Question 4

Give examples of AWS Lambda event sources.

Answer 4

• S3 (file upload)
• API Gateway (HTTP request)
• DynamoDB
• CloudWatch
• SNS / SQS

Question 5

Describe the flow when a file is uploaded to S3 and triggers Lambda.

Answer 5

File uploaded to S3
Event notification sent
Lambda function triggered
Code executes
Output stored/logged

Question 6

What is the role of API Gateway with Lambda?

Answer 6

It allows Lambda to be triggered via HTTP requests, enabling APIs.

Question 7

Why is Lambda ideal for microservices architectures?

Answer 7

Because functions are:
* Independent
* Scalable
* Event-driven

Question 8

How does Lambda scale automatically?

Answer 8

AWS automatically creates multiple function instances based on incoming events.

Question 9

What is a key benefit of Lambda in terms of cost?

Answer 9

You only pay for:
* Execution time
* Number of requests

(No cost when idle)

Question 10

What is the Lambda pricing model based on?

Answer 10

• Number of requests
• Duration of execution
• Memory allocated

Question 11

Why is Lambda considered cost-efficient?

Answer 11

Because there is no charge when the function is not running.

Question 12

What is the maximum execution time for a Lambda function?

Answer 12

15 minutes

Question 13

What happens if a Lambda function exceeds its execution time?

Answer 13

It is terminated automatically.

Question 14

What is the deployment package in Lambda?

Answer 14

A ZIP file containing:
* Code
* Dependencies

Question 15

What languages are supported by Lambda?

Answer 15

Common ones include:
* Python
* Node.js
* Java
* C#

Question 16

What is IAM’s role in Lambda?

Answer 16

It controls permissions, allowing Lambda to access other AWS services securely.

Question 17

Why must Lambda functions have IAM roles?

Answer 17

To grant secure access to resources like S3, DynamoDB, etc.

Question 18

What is concurrency in Lambda?

Answer 18

The number of function instances running simultaneously.

Question 19

What happens when many events trigger Lambda at once?

Answer 19

Lambda automatically scales to handle multiple concurrent executions.

Question 20

What is a common limitation of Lambda?

Answer 20

• Execution time limit
• Not suitable for long-running processes

Question 21

When should Lambda NOT be used?

Answer 21

• Long-running applications
• Stateful workloads
• Heavy continuous processing

Question 22

A user uploads images that need resizing automatically. What should be used?

Answer 22

S3 trigger + Lambda

Question 23

A REST API backend is needed without managing servers. Best solution?

Answer 23

API Gateway + Lambda

Question 24

An application runs continuously for hours. Should Lambda be used? Why?

Answer 24

No.
Because Lambda has a 15-minute execution limit.

Question 25

A system experiences unpredictable spikes in traffic. Why is Lambda ideal?

Answer 25

Because it automatically scales without manual provisioning.

Question 26

Why does Lambda reduce operational overhead?

Answer 26

Because AWS manages: * Servers * Scaling * Maintenance

Question 27

Do you pay for Lambda when no requests are made?

Answer 27

No

Question 28

Explain how Lambda integrates with other AWS services.

Answer 28

Lambda acts as a processing layer triggered by services like: * S3 * API Gateway * DynamoDB * CloudWatch

Question 29

What is the benefit of combining Lambda with S3 and DynamoDB?

Answer 29

To build fully serverless applications with automatic processing and storage.

Question 30

Explain a complete serverless architecture using Lambda.

Answer 30

* User sends request via API Gateway * Lambda processes request * Data stored in DynamoDB/S3 * Lambda scales automatically * No servers managed