Answers: <pre><code>Resources:                                                                                                                                                                                  
      TargetGroup:                                                                                                                                                                              
          Type: AWS::ElasticLoadBalancingV2::TargetGroup                                                                                                                                        
          Properties:                                                                                                                                                                           
            VpcId:                                                                                                                                                                              
              Fn::ImportValue:                                                                                                                                                                  
                !Sub "${Prefix}-VpcId"                                                                                                                                                          
            TargetType: instance                                                                                                                                                                
            Port: 443                                                                                                                                                                           
            Protocol: HTTPS                                                                                                                                                                     
      AutoScalingGroup:                                                                                                                                                                         
          Type: AWS::AutoScaling::AutoScalingGroup                                                                                                                                              
          Properties:                                                                                                                                                                           
            AutoScalingGroupName: Autoscaling Group Alpha                                                                                                                                       
            Cooldown: "120"                                                                                                                                                                     
            DesiredCapacity: "1"                                                                                                                                                                
            LaunchConfigurationName: AlphaLaunchConfiguration                                                                                                                                   
            MaxSize: "1"                                                                                                                                                                        
            MinSize: "1"                                                                                                                                                                        
            Tags:                                                                                                                                                                               
              -                                                                                                                                                                                 
                Key: Name                                                                                                                                                                       
                Value: Alpha ASG                                                                                                                                                                
                PropagateAtLaunch: true                                                                                                                                                         
            TargetGroupARNs:                                                                                                                                                                    
              - Ref: TargetGroup
  </code></pre>
  
  <p>As the error message states, TargetGroupARNs value should be of type List.
  <a href="https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html#cfn-as-group-targetgrouparns" rel="nofollow noreferrer">https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html#cfn-as-group-targetgrouparns</a></p>
  
Answers: CC BY-SA 4.0
Answers: 2019-12-23T09:49:24.410Z
Answers: 2019-12-23T09:49:24.410Z
Answers: vissree
Answers: <p>Changing the value of &quot;TargetGroupARNs:&quot; from &quot;Ref: TargetGroup&quot; to &quot;- !Ref TargetGroup&quot; should solve
  the problem.</p>
  <p>Reference :<a href="https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html</a></p>
  
Answers: CC BY-SA 4.0
Answers: 2021-07-08T18:24:03.357Z
Answers: 2021-07-08T20:48:24.363Z
Answers: 2021-07-08T20:48:24.363Z
Answers: Kunal
Body: <p>I am trying to use cloudformation to setup a ASG and I have a target group which I would like to associate with the ASG. The target group is created okay but when I go to attach it to the ASG I get an error message. I'd like to be able to attach this as I want a ALB in front of the ASG</p>
  
  <p>Error message:</p>
  
  <pre><code>Value of property TargetGroupARNs must be of type List of String
  </code></pre>
  
  <p>Cloudformation code</p>
  
  <pre><code>TargetGroup:
      Type: AWS::ElasticLoadBalancingV2::TargetGroup
      Properties:
        VpcId: 
          Fn::ImportValue: 
            !Sub "${Prefix}-VpcId"
        TargetType: instance
        Port: 443
        Protocol: HTTPS
  AutoScalingGroup:
      Type: AWS::AutoScaling::AutoScalingGroup
      Properties:
        AutoScalingGroupName: Autoscaling Group Alpha
        Cooldown: 120
        DesiredCapacity: 1
        LaunchConfigurationName: AlphaLaunchConfiguration
        MaxSize: 1
        MinSize: 1
        Tags:
          - 
            Key: Name
            Value: Alpha ASG
            PropagateAtLaunch: 'true'
        TargetGroupARNs:
          Ref: TargetGroup
  </code></pre>
  
Comments: CC BY-SA 4.0
Comments: 2019-12-20T11:42:49.510Z
Comments: Did you solve the issue? It seems that `TargetGroupARNs` is neither a `List` or `String`.
Comments: 030
Tags: <autoscaling><aws-cloudformation>
Title: Cloudformation issue with target groups and ASG
UserDisplayName: joshk132
ThreadText: # Cloudformation issue with target groups and ASG
  
  (Asked by: username_0 on 2019-10-24)
  
  I am trying to use cloudformation to setup a ASG and I have a target group which I would like to associate with the ASG. The target group is created okay but when I go to attach it to the ASG I get an error message. I'd like to be able to attach this as I want a ALB in front of the ASG
  
  Error message:
  
  ```
  Value of property TargetGroupARNs must be of type List of String
  
  ```
  
  Cloudformation code
  
  ```
  TargetGroup:
      Type: AWS::ElasticLoadBalancingV2::TargetGroup
      Properties:
        VpcId: 
          Fn::ImportValue: 
            !Sub "${Prefix}-VpcId"
        TargetType: instance
        Port: 443
        Protocol: HTTPS
  AutoScalingGroup:
      Type: AWS::AutoScaling::AutoScalingGroup
      Properties:
        AutoScalingGroupName: Autoscaling Group Alpha
        Cooldown: 120
        DesiredCapacity: 1
        LaunchConfigurationName: AlphaLaunchConfiguration
        MaxSize: 1
        MinSize: 1
        Tags:
          - 
            Key: Name
            Value: Alpha ASG
            PropagateAtLaunch: 'true'
        TargetGroupARNs:
          Ref: TargetGroup
  
  ```
  
  **Tags:** autoscaling, aws-cloudformation
  
  > **Comments:**
  > **username_1**: Did you solve the issue? It seems that `TargetGroupARNs` is neither a `List` or `String`.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2019-12-23. Score: 2
  
  ```
  Resources:                                                                                                                                                                                  
      TargetGroup:                                                                                                                                                                              
          Type: AWS::ElasticLoadBalancingV2::TargetGroup                                                                                                                                        
          Properties:                                                                                                                                                                           
            VpcId:                                                                                                                                                                              
              Fn::ImportValue:                                                                                                                                                                  
                !Sub "${Prefix}-VpcId"                                                                                                                                                          
            TargetType: instance                                                                                                                                                                
            Port: 443                                                                                                                                                                           
            Protocol: HTTPS                                                                                                                                                                     
      AutoScalingGroup:                                                                                                                                                                         
          Type: AWS::AutoScaling::AutoScalingGroup                                                                                                                                              
          Properties:                                                                                                                                                                           
            AutoScalingGroupName: Autoscaling Group Alpha                                                                                                                                       
            Cooldown: "120"                                                                                                                                                                     
            DesiredCapacity: "1"                                                                                                                                                                
            LaunchConfigurationName: AlphaLaunchConfiguration                                                                                                                                   
            MaxSize: "1"                                                                                                                                                                        
            MinSize: "1"                                                                                                                                                                        
            Tags:                                                                                                                                                                               
              -                                                                                                                                                                                 
                Key: Name                                                                                                                                                                       
                Value: Alpha ASG                                                                                                                                                                
                PropagateAtLaunch: true                                                                                                                                                         
            TargetGroupARNs:                                                                                                                                                                    
              - Ref: TargetGroup
  
  ```
  
  As the error message states, TargetGroupARNs value should be of type List.
  <https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html#cfn-as-group-targetgrouparns>
  
  
  ---
  
  ### Answer by username_3 on 2021-07-08. Score: 0
  
  Changing the value of "TargetGroupARNs:" from "Ref: TargetGroup" to "- !Ref TargetGroup" should solve
  the problem.
  
  Reference :<https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-group.html>
  
  
  ---
  
  