Why serverless matters in AWS - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a serverless function handler in AWS Lambda.

AWS

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

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

A"Hello from Lambda!"

Bprint("Hello")

Cevent + context

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Using print instead of return

Returning None which gives no response

The Lambda handler must return a response, here a simple string message.

2fill in blank

medium

Complete the code to create an AWS Lambda function with a runtime environment.

AWS

resource "aws_lambda_function" "example" {
  function_name = "my_lambda"
  runtime       = [1]
  handler       = "index.lambda_handler"
  role          = aws_iam_role.lambda_role.arn
  filename      = "function.zip"
}

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

A"java8"

B"python2.7"

C"nodejs10.x"

D"python3.9"

Attempts:

3 left

💡 Hint

Common Mistakes

Using outdated runtimes

Choosing a runtime that doesn't match the code

Using a modern supported runtime like python3.9 ensures better performance and support.

3fill in blank

hard

Fix the error in the AWS SAM template to define a serverless function with correct memory size.

AWS

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: python3.9
      MemorySize: [1]

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

A512MB

B0.5GB

C512

D512MBs

Attempts:

3 left

💡 Hint

Common Mistakes

Adding units like MB or GB

Using decimal or string values

MemorySize must be an integer value in MB without units.

4fill in blank

hard

Fill both blanks to configure an API Gateway trigger for a Lambda function in Terraform.

AWS

resource "aws_lambda_permission" "apigw" {
  statement_id  = "AllowAPIGatewayInvoke"
  action        = [1]
  function_name = aws_lambda_function.my_lambda.function_name
  principal     = [2]
  source_arn    = aws_api_gateway_rest_api.myapi.execution_arn
}

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

A"lambda:InvokeFunction"

B"lambda:InvokeAsync"

C"apigateway.amazonaws.com"

D"events.amazonaws.com"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong action like InvokeAsync

Wrong principal service

The action must be 'lambda:InvokeFunction' and the principal is 'apigateway.amazonaws.com' to allow API Gateway to invoke Lambda.

5fill in blank

hard

Fill all three blanks to define a serverless function with environment variables and timeout in AWS SAM.

AWS

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: python3.9
      Timeout: [1]
      Environment:
        Variables:
          STAGE: [2]
          LOG_LEVEL: [3]

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

A30

B"prod"

C"INFO"

D300

Attempts:

3 left

💡 Hint

Common Mistakes

Setting timeout too high

Not quoting environment variable strings

Timeout is set to 30 seconds, STAGE environment variable to 'prod', and LOG_LEVEL to 'INFO' as strings.

Practice

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

easy

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

B. You get unlimited free storage space.

C. You must manually scale your application.

D. You don't have to manage or maintain servers.

Solution

1. Step 1: Understand serverless computing basics

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

2. Step 2: Identify the main benefit

   This removes the need for server maintenance and management by the user.

3. Final Answer:

   You don't have to manage or maintain servers. -> Option D

4. Quick Check:

   Serverless = No server management [OK]

Hint: Serverless means no server management needed [OK]

Common Mistakes:

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

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

easy

A. AWS Lambda

B. Amazon EC2

C. Amazon S3 Glacier

D. Amazon RDS

Solution

1. Step 1: Identify serverless AWS services

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

2. Step 2: Compare options

   EC2 and RDS require server management; S3 Glacier is storage, not compute.

3. Final Answer:

   AWS Lambda -> Option A

4. Quick Check:

   Lambda = serverless compute [OK]

Hint: Lambda is AWS's serverless compute service [OK]

Common Mistakes:

• Choosing EC2 which needs server setup
• Confusing storage services with serverless compute
• Picking RDS which manages database servers

3. Consider this AWS Lambda usage scenario: You run a function that processes 1000 requests in a minute. How does serverless pricing affect your cost?

medium

A. You pay a flat fee for unlimited requests per month.

B. You pay for the maximum number of concurrent requests allowed.

C. You pay only for the compute time used during those 1000 requests.

D. You pay for the total number of servers running your function.

Solution

1. Step 1: Understand serverless pricing model

   Serverless charges based on actual compute time and number of requests.

2. Step 2: Apply to scenario

   For 1000 requests, you pay only for the compute time those requests consume, not fixed fees or server counts.

3. Final Answer:

   You pay only for the compute time used during those 1000 requests. -> Option C

4. Quick Check:

   Serverless pricing = pay per use [OK]

Hint: Serverless charges only for actual compute time used [OK]

Common Mistakes:

• Assuming flat monthly fees
• Thinking payment depends on server count
• Confusing concurrency limits with billing

4. You wrote a serverless function but it fails to handle sudden traffic spikes, causing errors. What is the likely cause?

medium

A. The function has a fixed number of instances and does not auto-scale.

B. Serverless functions automatically scale, so the error is unrelated to scaling.

C. The function's timeout setting is too high.

D. The function is not connected to a database.

Solution

1. Step 1: Understand serverless scaling

   Serverless functions usually auto-scale, but concurrency limits or misconfigurations can restrict it to a fixed number of instances.

2. Step 2: Identify cause of errors

   If the function does not scale beyond a fixed number, it cannot handle traffic spikes, causing errors.

3. Final Answer:

   The function has a fixed number of instances and does not auto-scale. -> Option A

4. Quick Check:

   Scaling limits cause errors under load [OK]

Hint: Check if auto-scaling limits block traffic handling [OK]

Common Mistakes:

• Assuming serverless always scales without limits
• Blaming timeout when scaling is the issue
• Ignoring connection issues unrelated to scaling

5. You want to build a photo-sharing app that automatically adjusts capacity as users upload photos. Which serverless feature best supports this?

hard

A. Fixed monthly billing for predictable costs.

B. Automatic scaling of compute resources based on demand.

C. Manual server provisioning to control capacity.

D. Dedicated servers for consistent performance.

Solution

1. Step 1: Identify app needs

   The app must handle varying user uploads, so capacity must adjust automatically.

2. Step 2: Match serverless feature

   Automatic scaling lets compute resources grow or shrink with demand, ideal for this app.

3. Final Answer:

   Automatic scaling of compute resources based on demand. -> Option B

4. Quick Check:

   Serverless auto-scales to match user demand [OK]

Hint: Auto-scaling matches resources to user demand [OK]

Common Mistakes:

• Choosing fixed billing which doesn't scale
• Thinking manual provisioning is needed
• Assuming dedicated servers are serverless