Why serverless architecture matters in AWS - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a serverless function using AWS Lambda.

AWS

def handler(event, context):
    return [1]

Drag options to blanks, or click blank then click option'

Aprint("Hello")

Bevent

Ccontext

D"Hello from Lambda!"

Attempts:

3 left

💡 Hint

Common Mistakes

Using print instead of return

Returning the event or context object directly

The Lambda function should return a string as the response. Returning a string like "Hello from Lambda!" is correct.

2fill in blank

medium

Complete the code to create an AWS Lambda function trigger from an API Gateway event.

AWS

def handler(event, context):
    if event["httpMethod"] == [1]:
        return {"statusCode": 200, "body": "Success"}

Drag options to blanks, or click blank then click option'

A"GET"

B"POST"

C"PUT"

D"DELETE"

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST or PUT instead of GET

Missing quotes around the method string

The API Gateway event includes the HTTP method in the "httpMethod" key. To handle a GET request, the value should be "GET".

3fill in blank

hard

Fix the error in the AWS SAM template to define a Lambda function resource.

AWS

Resources:
  MyFunction:
    Type: [1]
    Properties:
      Handler: index.handler
      Runtime: python3.9
      CodeUri: ./src/

Drag options to blanks, or click blank then click option'

A"AWS::Serverless::Function"

B"AWS::S3::Bucket"

C"AWS::Lambda::Function"

D"AWS::EC2::Instance"

Attempts:

3 left

💡 Hint

Common Mistakes

Using AWS::Lambda::Function instead of AWS::Serverless::Function

Using unrelated resource types

In AWS SAM templates, Lambda functions are defined with the type "AWS::Serverless::Function" to enable serverless features.

4fill in blank

hard

Fill both blanks to configure an AWS Lambda function with environment variables and memory size.

AWS

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      MemorySize: [1]
      Environment:
        Variables:
          STAGE: [2]

Drag options to blanks, or click blank then click option'

A512

B"prod"

C"dev"

D128

Attempts:

3 left

💡 Hint

Common Mistakes

Using strings for MemorySize

Using numbers without quotes for environment variables

The MemorySize property expects an integer value like 512 (MB). Environment variables are strings, so "dev" is a valid stage name.

5fill in blank

hard

Fill all three blanks to create a serverless function with an S3 trigger and proper permissions.

AWS

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: python3.9
      Events:
        S3Event:
          Type: S3
          Properties:
            Bucket: [1]
            Events: [2]
      Policies:
        - [3]

Drag options to blanks, or click blank then click option'

A"my-upload-bucket"

B"s3:ObjectCreated:*"

C"AmazonS3ReadOnlyAccess"

D"arn:aws:s3:::my-upload-bucket"

Attempts:

3 left

💡 Hint

Common Mistakes

Using ARN instead of bucket name for Bucket

Incorrect event string

Wrong policy name

The S3 event trigger requires the bucket name as a string, the event type as "s3:ObjectCreated:*", and the policy to allow read access is "AmazonS3ReadOnlyAccess".

Practice

1. What is the main benefit of using serverless architecture in cloud computing?

easy

A. You don't need to manage or provision servers.

B. You get unlimited free storage.

C. You must manually scale your application.

D. You pay a fixed monthly fee regardless of usage.

Solution

1. Step 1: Understand serverless basics

   Serverless means the cloud provider manages servers, so you don't have to.

2. Step 2: Identify the key benefit

   This removes the need for manual server management and provisioning.

3. Final Answer:

   You don't need to manage or provision servers. -> Option A

4. Quick Check:

   Serverless = No server management [OK]

Hint: Serverless means no server setup or maintenance needed [OK]

Common Mistakes:

• Thinking serverless means free unlimited resources
• Assuming you must scale servers manually
• Believing serverless has fixed monthly costs

2. Which AWS service is an example of serverless compute?

easy

A. Amazon EC2

B. AWS Lambda

C. Amazon RDS

D. Amazon S3

Solution

1. Step 1: Identify serverless compute services

   AWS Lambda runs code without managing servers, fitting serverless compute.

2. Step 2: Compare options

   EC2 requires server management, RDS is managed database, S3 is storage.

3. Final Answer:

   AWS Lambda -> Option B

4. Quick Check:

   Serverless compute = AWS Lambda [OK]

Hint: Lambda runs code without servers, EC2 does not [OK]

Common Mistakes:

• Choosing EC2 which requires server management
• Confusing storage (S3) with compute
• Selecting RDS which is managed database, not compute

3. Consider this AWS Lambda function code snippet:

exports.handler = async (event) => {
  return { statusCode: 200, body: 'Hello Serverless!' };
};

What will be the output when this Lambda function is invoked?

medium

A. Runtime error because of missing callback

B. SyntaxError due to arrow function

C. { statusCode: 200, body: 'Hello Serverless!' }

D. Empty response with statusCode 500

Solution

1. Step 1: Analyze the Lambda handler syntax

   The handler is an async arrow function returning a valid response object.

2. Step 2: Understand Lambda response behavior

   Returning an object with statusCode and body is correct for API Gateway integration.

3. Final Answer:

   { statusCode: 200, body: 'Hello Serverless!' } -> Option C

4. Quick Check:

   Async handler returns response object [OK]

Hint: Async arrow functions can return response objects directly [OK]

Common Mistakes:

• Thinking arrow functions cause syntax errors
• Assuming callback is required in async handlers
• Expecting empty or error responses without cause

4. You wrote this AWS Lambda function but it always times out:

exports.handler = (event, context) => {
  while(true) {}
};

What is the main reason for the timeout?

medium

A. Lambda functions cannot use arrow functions.

B. Missing async keyword causes timeout.

C. The event parameter is not used.

D. The infinite loop blocks the function from returning.

Solution

1. Step 1: Identify the code behavior

   The while(true) creates an infinite loop that never ends or returns.

2. Step 2: Understand Lambda timeout cause

   Without returning or ending, Lambda runs until timeout is reached.

3. Final Answer:

   The infinite loop blocks the function from returning. -> Option D

4. Quick Check:

   Infinite loop causes timeout [OK]

Hint: Infinite loops cause Lambda to never finish [OK]

Common Mistakes:

• Blaming missing async keyword for timeout
• Thinking arrow functions are unsupported
• Assuming unused parameters cause timeout

5. You want to build a web app that scales automatically and only charges you when users interact. Which serverless feature best supports this?

hard

A. Automatic scaling with pay-per-use billing

B. Reserved instances with fixed monthly cost

C. Manual server provisioning for control

D. Pre-allocated capacity to avoid cold starts

Solution

1. Step 1: Identify serverless scaling and billing

   Serverless automatically scales with demand and charges only for actual usage.

2. Step 2: Compare options for cost and scaling

   Reserved instances and manual provisioning do not scale automatically or charge per use.

3. Final Answer:

   Automatic scaling with pay-per-use billing -> Option A

4. Quick Check:

   Serverless = scale automatically + pay per use [OK]

Hint: Serverless scales automatically and bills only when used [OK]

Common Mistakes:

• Choosing reserved instances which have fixed costs
• Thinking manual provisioning is needed for scaling
• Believing pre-allocated capacity is required in serverless