子参数参数的Cloudformation嵌套堆栈模板ValidationError

Question

我制作了一个嵌套的cloudformation父模板，然后引用了4个子模板。 当我尝试通过CLI命令aws cloudformation create-stack...启动堆栈时，出现错误：

An error occurred (ValidationError) when calling the CreateStack 
operation: Template error: instance of Fn::GetAtt references undefined 
resource BatchScatterGatherSubmissionActivity

这是因为我有一个名为StepFunctionResourcesStack的子模板，其中包含BatchScatterGatherSubmissionActivity ，然后是另一个引用它的子模板EC2InstanceResourcesStack 。 我确保为后一个子模板添加一个DependsOn子句，但是仍然出现错误。

这是StepFunctionResourcesStack ：

---

AWSTemplateFormatVersion: '2010-09-09'
Description: step functions resources stack.
Parameters:
  StackUID:
    Type: String 

Resources:
  StatesExecutionRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Service:
                - !Sub states.${AWS::Region}.amazonaws.com
            Action: "sts:AssumeRole"
      Path: "/"
      Policies:
        - PolicyName: StatesExecutionPolicy
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: Allow
                Action:
                  - "lambda:InvokeFunction"
                Resource: "*"

  MyStateMachine:
    Type: "AWS::StepFunctions::StateMachine"
    Properties:
      #
      # The StateMachine definition is substituted in with Jinja2
      #
      DefinitionString: !Sub
        - |
          {{ machine_json | indent(10) }}
        - {% for item in machine_args -%}
          {{ item }}
          {% endfor %}

      RoleArn: !GetAtt [ StatesExecutionRole, Arn ]

  # several of these:

  BatchScatterGatherSubmissionActivity:
    Type: "AWS::StepFunctions::Activity"
    Properties:
      Name:
        Fn::Join: [ "-", [ "BatchScatterGatherSubmissionActivity", Ref: StackUID] ]

  BatchScatterGatherPollingActivity:
    Type: "AWS::StepFunctions::Activity"
    Properties:
      Name:
        Fn::Join: [ "-", [ "BatchScatterGatherPollingActivity", Ref: StackUID] ]

  BatchGatherActivity:
    Type: "AWS::StepFunctions::Activity"
    Properties:
      Name:
        Fn::Join: [ "-", [ "BatchGatherActivity", Ref: StackUID] ]

  BatchTriodenovoActivity:
    Type: "AWS::StepFunctions::Activity"
    Properties:
      Name:
        Fn::Join: [ "-", [ "BatchTriodenovoActivity", Ref: StackUID] ]

  BatchHandoffActivity:
    Type: "AWS::StepFunctions::Activity"
    Properties:
      Name:
        Fn::Join: [ "-", [ "BatchHandoffActivity", Ref: StackUID] ]    

Outputs:
  # These get used in the instance_resources child stack.
  BatchScatterGatherSubmissionActivity:
    Value: !Ref BatchScatterGatherSubmissionActivity
  BatchScatterGatherPollingActivity:
    Value: !Ref BatchScatterGatherPollingActivity
  BatchGatherActivity:
    Value: !Ref BatchGatherActivity
  BatchTriodenovoActivity:
    Value: !Ref BatchTriodenovoActivity
  BatchHandoffActivity:
    Value: !Ref BatchHandoffActivity

这是父（嵌套）模板的相关部分，上面的输出将传递到EC2InstanceResourcesStack中：

  StepFunctionResourcesStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      Parameters:
        StackUID:
          Ref: StackUID
      TemplateURL: https://s3.amazonaws.com/CFNTemplate/step_functions_resources.stack.yaml
      Timeout: "100"  


  EC2InstanceResourcesStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      Parameters:
        BatchScatterGatherSubmissionActivity: 
          Fn::GetAtt: [ "BatchScatterGatherSubmissionActivity", "Outputs.StepFunctionResourcesStack" ]
        BatchScatterGatherPollingActivity: 
          Fn::GetAtt: [ "BatchScatterGatherPollingActivity", "Outputs.StepFunctionResourcesStack" ]
        BatchGatherActivity: 
          Fn::GetAtt: [ "BatchGatherActivity", "Outputs.StepFunctionResourcesStack" ]
        BatchTriodenovoActivity: 
          Fn::GetAtt: [ "BatchTriodenovoActivity", "Outputs.StepFunctionResourcesStack" ]
        BatchHandoffActivity: 
          Fn::GetAtt: [ "BatchHandoffActivity", "Outputs.StepFunctionResourcesStack" ]
        Subnet: !Ref Subnet
        GPCESSHKeyPair: !Ref GPCESSHKeyPair
        GPCESubnetAZ1: !Ref GPCESubnetAZ1
        ActivityAndHandoffAnsibleBucketName: !Ref ActivityAndHandoffAnsibleBucketName
        ActivityAndHandoffAnsibleKeyName: !Ref ActivityAndHandoffAnsibleKeyName
        ActivityAndHandoffDaemonBucketName: !Ref ActivityAndHandoffDaemonBucketName
        ActivityAndHandoffDaemonKeyName: !Ref ActivityAndHandoffDaemonKeyName
        ActivityAndHandoffDaemonRequirementsBucketName: !Ref ActivityAndHandoffDaemonRequirementsBucketName
        ActivityAndHandoffDaemonRequirementsKeyName: !Ref ActivityAndHandoffDaemonRequirementsKeyName
        Rkstr8PkgBucketName: !Ref Rkstr8PkgBucketName
        Rkstr8PkgKeyName: !Ref Rkstr8PkgKeyName
      TemplateURL: https://s3.amazonaws.com/CFNTemplate/instance_resources.stack.yaml
      Timeout: "100"
    DependsOn: StepFunctionResourcesStack

对于从子级导出参数并将其通过父模板传递给另一个参数的方法，我遵循此处答案中提供的方法： AWS CloudFormation：在嵌套堆栈之间传递值

Answer 1

您不能直接从另一个模板中的一个模板（通过Ref ）引用资源，即使它们是父子模板或同级模板。 资源是特定于堆栈的，除非它们通过“ Output部分显式导出。

因此，您有2个选择：

选项1：通过“ Output部分从子模板1导出您关心的BatchScatterGatherSubmissionActivity值，然后将这些值导入子模板2。

例如：

在“源”模板中：

"Outputs" : {
  "MyValue" : {
    "Value" : {
      "Ref" : "BatchScatterGatherSubmissionActivity"
    },
    "Export" : {
      "Name" : "MyExportedValue"
    }
  }
}

然后将值导入“消费”模板中：

{ "Fn::ImportValue" : "MyExportedValue" }

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

缺点之一是您不能“ DependsOn”。 而且，从字面上看，子模板2取决于子模板1。

选项2：从子模板输出您关心BatchScatterGatherSubmissionActivity的值（即，向上传递给父级），然后将这些值从父级传递到另一个子级。

因此，在子模板1中，您将从子堆栈中输出值：

"Outputs" : {
  "MyValue" : {
    "Value" : {
      "Ref" : "BatchScatterGatherSubmissionActivity"
    }
  }
}

在子模板2中，您可以通过“参数”部分向模板添加一个参数，然后引用该参数。

"Parameters" : {
  "MyParam" : {
    "Type" : "String",
    "Description" : "The value from elsewhere"
  }
}

然后

{ "Ref" : "MyParam" }

最后，通过将子模板1的输出传递到子模板2的参数中，将2个子堆栈在父级中挂钩：

"ChildStack2": {
  "Type" : "AWS::CloudFormation::Stack",
  "Properties" : {
    "Parameters" : {
      "MyParam" : { "Fn::GetAtt" : "Outputs.MyValue" }
    }
  }
}

在这种情况下，直到子堆栈1准备好并输出其值时才创建子堆栈2，因此隐含了“ DependsOn”。 但是在这种情况下，子模板2不依赖于子模板1。相反，它取决于满足其输入参数的任何内容（可以是父堆栈，也可以是其他内容）。