PAS-C01 Migration Practice Question

Exhibit

Refer to the exhibit.

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Resources": {
    "MyEC2Instance": {
      "Type": "AWS::EC2::Instance",
      "Properties": {
        "ImageId": "ami-12345678",
        "InstanceType": "t2.micro"
      }
    }
  }
}

Refer to the exhibit. A CloudFormation template is used to migrate a web server to AWS. The template launches an EC2 instance but does not install the web server. What is the best way to automate the installation?

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Add a UserData property to the EC2 instance resource.

The UserData property in a CloudFormation EC2 resource allows you to specify scripts or commands that run automatically at instance launch. This is the simplest and most direct method to install software like a web server during provisioning. Option A (CloudWatch Events triggering Lambda) is not automatic at launch and requires additional resources. Option C (Run Command) requires manual invocation or scheduling, not automatic at launch. Option D (CodeDeploy) requires an agent to be pre-installed, which is not the case here.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Create a CloudWatch Events rule to trigger a Lambda function after instance launch.
Why it's wrong here
Creating a CloudWatch Events rule to trigger a Lambda function is unsuitable for initial web server installation because Lambda does not directly execute commands within a newly launched EC2 instance. This approach requires additional mechanisms like SSM Agent and Run Command for remote execution, which are not implicitly part of this solution. It is tempting because CloudWatch Events can react to EC2 state changes, making it ideal for post-launch operational tasks such as sending notifications, enforcing tagging policies, or initiating external management processes, rather than direct instance provisioning.
✓
Add a UserData property to the EC2 instance resource.
Why this is correct
UserData runs scripts during instance initialization.
✗
Use AWS Systems Manager Run Command to install the web server.
Why it's wrong here
Run Command is manual or requires a schedule, not automatic at launch.
✗
Use AWS CodeDeploy to deploy the web server after the instance is created.
Why it's wrong here
CodeDeploy requires the CodeDeploy agent on the instance.

Quick reference

Cloud Service Model Comparison

Model	You Manage	Provider Manages	Examples
IaaS	OS, runtime, apps, data	Hardware, hypervisor, networking	EC2, Azure VMs, GCP Compute Engine
PaaS	Apps and data	OS, runtime, middleware, hardware	Elastic Beanstalk, Azure App Service
SaaS	Data and settings only	Everything else	Microsoft 365, Salesforce, Workday
FaaS / Serverless	Function code only	Infra, scaling, runtime	Lambda, Azure Functions, Cloud Run
CaaS	Containers and apps	Kubernetes, OS, hardware	EKS, AKS, GKE

Go deeper

PAS-C01 Migration Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

Cloud Service Model Comparison

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