Nested stacks for modularity in AWS - Mini Project: Build & Apply

Nested stacks for modularity

📖 Scenario: You are building a cloud infrastructure using AWS CloudFormation. To keep your templates clean and reusable, you want to split your infrastructure into smaller parts using nested stacks.Imagine you have a main template that includes a network stack and a compute stack as nested stacks.

🎯 Goal: Create a main CloudFormation template that uses nested stacks for network and compute resources. Each nested stack should be referenced properly to keep the infrastructure modular and organized.

📋 What You'll Learn

Create a main CloudFormation template with two nested stacks: NetworkStack and ComputeStack.

Define the nested stacks using the AWS::CloudFormation::Stack resource type.

Use parameters to pass the VpcId from the network stack to the compute stack.

Ensure the nested stacks are referenced with the correct template URLs.

💡 Why This Matters

🌍 Real World

Large cloud infrastructures are often split into smaller templates to improve readability and reuse. Nested stacks allow teams to manage parts of infrastructure independently.

💼 Career

Cloud architects and DevOps engineers use nested stacks to modularize infrastructure as code, making deployments safer and easier to maintain.

1

Create the main CloudFormation template skeleton

Create a CloudFormation template called main_template.yaml with an empty Resources section.

AWS

Resources:
  # Your code here

Need a hint?

Start with the basic CloudFormation template structure including AWSTemplateFormatVersion and Resources.

2

Add the NetworkStack nested stack resource

In main_template.yaml, add a resource called NetworkStack of type AWS::CloudFormation::Stack with a TemplateURL set to https://s3.amazonaws.com/mybucket/network.yaml.

AWS

AWSTemplateFormatVersion: '2010-09-09'
Description: Main template with nested stacks
Resources:
  NetworkStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/mybucket/network.yaml
  # Your code here

Need a hint?

Use the AWS::CloudFormation::Stack resource type and set the TemplateURL to the network stack template location.

3

Add the ComputeStack nested stack with parameter passing

In main_template.yaml, add a resource called ComputeStack of type AWS::CloudFormation::Stack. Set its TemplateURL to https://s3.amazonaws.com/mybucket/compute.yaml and pass the VpcId parameter from the output of NetworkStack using Fn::GetAtt with attribute Outputs.VpcId.

AWS

AWSTemplateFormatVersion: '2010-09-09'
Description: Main template with nested stacks
Resources:
  NetworkStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/mybucket/network.yaml
  ComputeStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/mybucket/compute.yaml
      Parameters:
        VpcId: !GetAtt NetworkStack.Outputs.VpcId
  # Your code here

Need a hint?

Use Parameters to pass VpcId from NetworkStack outputs using !GetAtt NetworkStack.Outputs.VpcId.

4

Complete the main template with description and resources

Ensure the main_template.yaml includes the AWSTemplateFormatVersion, a Description, and both nested stack resources NetworkStack and ComputeStack with their properties as specified.

AWS

AWSTemplateFormatVersion: '2010-09-09'
Description: Main template with nested stacks
Resources:
  NetworkStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/mybucket/network.yaml
  ComputeStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/mybucket/compute.yaml
      Parameters:
        VpcId: !GetAtt NetworkStack.Outputs.VpcId
# Your code here

Need a hint?

Review the entire template to ensure all required parts are included and correctly formatted.