Creating stacks in AWS - Try It Yourself

Creating stacks

📖 Scenario: You are working as a cloud engineer for a small company. Your team wants to automate the creation of cloud resources using AWS CloudFormation stacks. You will create a simple CloudFormation stack that provisions an Amazon S3 bucket.

🎯 Goal: Build a CloudFormation stack template step-by-step that creates an Amazon S3 bucket with a specific name.

📋 What You'll Learn

Create a CloudFormation template dictionary with the required keys

Add a Parameters section to specify the bucket name

Add a Resources section to create an S3 bucket using the parameter

Add Outputs section to export the bucket name

💡 Why This Matters

🌍 Real World

CloudFormation templates automate cloud resource creation, saving time and reducing errors.

💼 Career

Cloud engineers and DevOps professionals use CloudFormation to manage infrastructure as code.

1

Create the initial CloudFormation template dictionary

Create a dictionary called template with the key AWSTemplateFormatVersion set to '2010-09-09' and an empty Resources dictionary.

AWS

# Create the initial CloudFormation template dictionary
# Your code here

Hint

Start by defining a Python dictionary with the required keys for a CloudFormation template.

2

Add Parameters section for bucket name

Add a Parameters key to the template dictionary. Inside it, create a parameter called BucketName with Type set to String and Description set to 'Name of the S3 bucket'.

AWS

template = {
    'AWSTemplateFormatVersion': '2010-09-09',
    'Resources': {}
}
# Add Parameters section with BucketName parameter
# Your code here

Hint

Parameters allow users to input values when creating the stack. Add the BucketName parameter inside the Parameters dictionary.

3

Add S3 bucket resource using the parameter

Add a resource called MyS3Bucket inside the Resources dictionary of template. Set its Type to AWS::S3::Bucket and its Properties to use the BucketName parameter with { 'Ref': 'BucketName' }.

AWS

template = {
    'AWSTemplateFormatVersion': '2010-09-09',
    'Parameters': {
        'BucketName': {
            'Type': 'String',
            'Description': 'Name of the S3 bucket'
        }
    },
    'Resources': {}
}
# Add MyS3Bucket resource using BucketName parameter
# Your code here

Hint

Resources define the AWS services to create. Use the Ref function to refer to the parameter value.

4

Add Outputs section to export the bucket name

Add an Outputs key to the template dictionary. Inside it, create an output called BucketNameOutput with Description set to 'The name of the S3 bucket' and Value set to { 'Ref': 'MyS3Bucket' }.

AWS

template = {
    'AWSTemplateFormatVersion': '2010-09-09',
    'Parameters': {
        'BucketName': {
            'Type': 'String',
            'Description': 'Name of the S3 bucket'
        }
    },
    'Resources': {
        'MyS3Bucket': {
            'Type': 'AWS::S3::Bucket',
            'Properties': {
                'BucketName': { 'Ref': 'BucketName' }
            }
        }
    }
}
# Add Outputs section with BucketNameOutput
# Your code here

Hint

Outputs allow you to see important information after stack creation. Use Ref to get the resource's name.

Practice

1. What is the main purpose of creating a stack in AWS CloudFormation?

easy

A. To group related cloud resources for easy management

B. To write code for AWS Lambda functions

C. To monitor AWS billing and usage

D. To create user accounts in AWS IAM

Solution

1. Step 1: Understand what a stack represents

   A stack is a collection of AWS resources that you manage as a single unit.

2. Step 2: Identify the purpose of grouping resources

   Grouping resources simplifies deployment, updates, and deletion.

3. Final Answer:

   To group related cloud resources for easy management -> Option A

4. Quick Check:

   Stack = Group resources [OK]

Hint: Stacks group resources to manage them together [OK]

Common Mistakes:

• Confusing stacks with user accounts
• Thinking stacks are for billing
• Mixing stacks with Lambda code writing

2. Which AWS CLI command is used to create a stack from a template file named template.yaml?

easy

A. aws s3 create-bucket --template template.yaml

B. aws cloudformation create-stack --stack-name MyStack --template-body file://template.yaml

C. aws cloudformation deploy --stack-name MyStack --template-file file://template.yaml

D. aws ec2 create-stack --template-file template.yaml

Solution

1. Step 1: Identify the correct AWS service and command

   Creating stacks uses the AWS CloudFormation service and the command is create-stack.

2. Step 2: Check the correct syntax for template file input

   The template file is specified with --template-body file://filename.

3. Final Answer:

   aws cloudformation create-stack --stack-name MyStack --template-body file://template.yaml -> Option B

4. Quick Check:

   Use create-stack with --template-body file:// [OK]

Hint: Use create-stack with --template-body file:// [OK]

Common Mistakes:

• Using wrong AWS service like EC2 or S3
• Using --template-file instead of --template-body
• Confusing create-stack with deploy command

3. Given this AWS CLI command:
aws cloudformation create-stack --stack-name TestStack --template-body file://template.yaml --parameters ParameterKey=Env,ParameterValue=prod
What will happen when this command runs?

medium

A. The command will fail because parameters must be in JSON format

B. The stack will be created with default parameter values ignoring Env

C. The stack will be created but the Env parameter will be ignored

D. A stack named TestStack is created using the template with Env parameter set to prod

Solution

1. Step 1: Understand parameter usage in create-stack command

   The --parameters option allows passing key-value pairs to customize the stack.

2. Step 2: Check the syntax correctness

   The syntax ParameterKey=Env,ParameterValue=prod is valid for AWS CLI parameters.

3. Final Answer:

   A stack named TestStack is created using the template with Env parameter set to prod -> Option D

4. Quick Check:

   Parameters customize stack creation [OK]

Hint: Parameters use ParameterKey= and ParameterValue= pairs [OK]

Common Mistakes:

• Thinking parameters must be JSON
• Assuming parameters are ignored if passed
• Confusing parameter syntax with other commands

4. You run this command to create a stack:
aws cloudformation create-stack --stack-name MyStack --template-body file://template.yaml
But you get an error: Template format error: YAML not well-formed.
What is the most likely cause?

medium

A. The template.yaml file has syntax errors in YAML formatting

B. The stack name MyStack is invalid

C. The AWS CLI command is missing the region parameter

D. The template file path is incorrect

Solution

1. Step 1: Analyze the error message

   The error says "YAML not well-formed" which means the template file has syntax issues.

2. Step 2: Check other possible causes

   Stack name and region issues cause different errors; file path errors cause file not found errors.

3. Final Answer:

   The template.yaml file has syntax errors in YAML formatting -> Option A

4. Quick Check:

   YAML errors cause template format error [OK]

Hint: Check YAML syntax carefully for formatting errors [OK]

Common Mistakes:

• Assuming stack name causes YAML errors
• Ignoring file path correctness
• Forgetting to check template syntax

5. You want to create a stack that launches an EC2 instance with a parameter to choose the instance type. Your template uses a parameter named InstanceType. Which AWS CLI command correctly creates the stack with t3.micro as the instance type?

hard

A. aws cloudformation deploy --stack-name EC2Stack --template-file file://ec2.yaml --parameter-overrides InstanceType=t3.micro

B. aws cloudformation create-stack --stack-name EC2Stack --template-body file://ec2.yaml --parameters InstanceType=t3.micro

C. aws cloudformation create-stack --stack-name EC2Stack --template-body file://ec2.yaml --parameters ParameterKey=InstanceType,ParameterValue=t3.micro

D. aws ec2 run-instances --instance-type t3.micro --template-file ec2.yaml

Solution

1. Step 1: Identify the correct command and syntax for stack creation with parameters

   The create-stack command uses --parameters ParameterKey=key,ParameterValue=value syntax.

2. Step 2: Verify the parameter key and value match the template

   The parameter key is InstanceType and value is t3.micro, correctly formatted in aws cloudformation create-stack --stack-name EC2Stack --template-body file://ec2.yaml --parameters ParameterKey=InstanceType,ParameterValue=t3.micro.

3. Final Answer:

   aws cloudformation create-stack --stack-name EC2Stack --template-body file://ec2.yaml --parameters ParameterKey=InstanceType,ParameterValue=t3.micro -> Option C

4. Quick Check:

   Use ParameterKey= and ParameterValue= for parameters [OK]

Hint: Use ParameterKey= and ParameterValue= pairs for parameters [OK]

Common Mistakes:

• Using wrong parameter syntax
• Confusing deploy with create-stack
• Using EC2 CLI instead of CloudFormation