Public-and-Private-Subnet-per-AZ

Summary

This is a Cloudformation Macro used to dynamically add a public and private subnet per Availability Zone when launching a template. When the CreateStack template is launched and a change set is created, the Macro (named 'CreateSubnetsPerAZ') will dynamically add resources to the template for a public and private subnet per available AZ

How to Use

• Create a stack using the CreateMacro template, which will create the Lambda function and register it as a CFN Macro (with the name: 'CreateSubnetsPerAZ')
• Now the Macro is registered in your AWS account, and you can reference this macro in any CFN template using a top-level resource, similar to the following:

Transform:
  - CreateSubnetsPerAZ

• Create a stack using the CreateStack template. The template contains a VPC with a public and private subnet. When this template is launched and the change set is created, the macro will add a private and public subnet to every AZ available in that region. If this template is launched in us-west-2, there will be 2 public and 2 private subnets. If launched in us-east-1, there will be 6 public and 6 private subnets

References

See the recently announced CloudFormation Macros feature: CloudFormation Macros

/HT

@mike-mosher