CloudFormation Pass All Parameters from Root Stack to Nested Stack

Question

Is there a way to pass every parameter that a root stack receives to its nested stacks? I can pass one parameter at a time just fine, but I'd like to just pass them all at once.

Answer 1

Here is sample template to give you an idea.

Master.yaml:

Resources:
  Cloudspan:
    Type: "AWS::CloudFormation::Stack"
    Properties:
      Parameters:
        LambdaName: Cloudspan
        BucketName: <BucketName>
        S3KeyName: <S3KeyName>
        FunctionName: <FunctionName>
      TemplateURL: <TemplateURL>
  Alignment:
    Type: "AWS::CloudFormation::Stack"
    Properties:
      Parameters:
        LambdaName: Alignment
        BucketName: <BucketName>
        S3KeyName: <S3KeyName>
        FunctionName: <FunctionName>
      TemplateURL: <TemplateURL>

Lambda-child.yaml:

Parameters:
  LambdaName:
    Type: String
  BucketName:
    Type: String
  S3KeyName:
    Type: String
  FunctionName:
    Type: String

Resources:
  LambdaFunction:
    Type: "AWS::Lambda::Function"
    Properties:
      Handler: !Sub '${LambdaName}-{FunctionName}.Handler'
      Role:
        Fn::GetAtt: ['LambdaExecutionRole', Arn ]
      Code:
        S3Bucket: !Sub '${LambdaName}{BucketName}'
        S3Key: !Sub '${LambdaName}{S3KeyName}'
      Runtime: "python3.6"

Answer 2

There is no way (yet) to pass every parameter at once from the root stack to the nested stack. If you want to pass every parameter, you have to do it one by one as the template given in Sudharsan Sivasankaran's answer.

Answer 3

Fn::Import

You can "export" your parameters as outputs from one stack and then any stack will be able to access those values across your entire account. This might be more open than you are looking for but if your end goal is to get stacks to share variables then exporting outputs and referencing them with Fn::Import accomplishes that.

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-stack-exports.html