Invalid template resource property 'ElbDomainName'

Question

For the below cloudformation template:

AWSTemplateFormatVersion: "2010-09-09"
Description: "Todobackend Stack"

# Stack Parameters
Parameters:
  VpcId:
    Type: "AWS::EC2::VPC::Id"
    Description: "The target VPC Id"
  SubnetId:
    Type: "AWS::EC2::Subnet::Id"
    Description: "The target Subnet Id in availability zone a"
  KeyPair:
    Type: "String"
    Description: "The key pair that is allowed SSH access"
  InstanceCount:
    Type: "Number"
    Description: "The desired number of application instances"
  DbSubnets:
    Type: "List<AWS::EC2::Subnet::Id>"
    Description: "The target DB Subnet Group subnet Ids"
  DbAvailabilityZone:
    Type: "String"
    Description: "The target availability zone for the database instance"
  DbUsername:
    Type: "String"
    Description: "The RDS database username"
  DbPassword:
    Type: "String"
    Description: "The RDS database password"
    NoEcho: "true"

# Stack Resources
Resources:
  # Configure auto scaing group
  AutoScalingGroup:
    Type: "AWS::AutoScaling::AutoScalingGroup"
    Properties:
      VPCZoneIdentifier: [ { "Ref": "SubnetId" } ]
      LaunchConfigurationName: { "Ref": "AutoScalingLaunchConfiguration" }
      MinSize: 0
      MaxSize: 2
      DesiredCapacity: { "Ref": "InstanceCount" }
      Tags:
        - Key: "Name"
          Value: { "Fn::Join": ["", [ { "Ref": "AWS::StackName" }, " -instance" ] ] }
          PropagateAtLaunch: "true"

  AutoScalingLaunchConfiguration:
    Type: "AWS::AutoScaling::LaunchConfiguration"
    Properties:
      ImageId: ami-05958d7635caa4d04
      InstanceType: t2.micro
      keyName: { "Ref": "KeyPair" }
      IamInstanceProfile: { "Ref": "EC2InstanceProfile" }
      SecurityGroups:
        - { "Ref": "EC2InstanceSecurityGroup" }
      UserData: {
        "Fn::Base64": { "Fn::Join": ["", [
          "#!/bin/bash\n",
          "echo ECS_CLUSTER=", { "Ref": "EcsCluster"}, " >> /etc/ecs/ecs.config\n"
        ] ] }
      }

  EC2InstanceSecurityGroup:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: "todobackend-sg"
      VpcId: { "Ref": "VpcId" }
      SecurityGroupIngress:
        - IpProtocol: "tcp"
          FromPort: "8080"
          ToPort: "8080"
          SourceSecurityGroupId: { "Ref": "ElbSecurityGroup" }
        - IpProtocol: "tcp"
          FromPort: "22"
          ToPort: "22"
          CidrIp: "0.0.0.0/0"
      Tags:
        - Key: "Name"
          Value: { "Fn::Join": ["", [ { "Ref": "AWS::StackName" }, "-instance-sg" ] ] }

  EC2InstanceProfile:
    Type: "AWS::IAM::InstanceProfile"
    Properties:
      Path: "/"
      Roles: [ { "Ref": "EC2InstanceRole" } ]

  EC2InstanceRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument: {
        "Version": "2012-10-17",
        "Statement": [
          {
            "Effect": "Allow",
            "Principal": { "Service": [ "ec2.amazonaws.com" ] },
            "Action": [ "sts:AssumeRole"]
          }
        ]
      }
      Path: "/"
      ManagePolicyArns:
        - "arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceForEc2Role"

  # Configure RDS
  DbInstance:
    Type: "AWS::RDS::DBInstance"
    Properties:
      DBSubnetGroupName: { "Ref": "DbSubnetGroup" }
      MultiAZ: "false"
      AvailabilityZone: { "Ref": "DBAvailabilityZone" }
      AllocatedStorage: 8
      StorageType: "gp2"
      DBInstanceClass: "db.t2.micro"
      DBName: "todobackend"
      Engine: "MySQL"
      EngineVersion: "5.6"
      MasterUserName: { "Ref": "DbUsername" }
      MasterUserPassword: { "Ref": "DbPassword" }
      VPCSecurityGroups:
        - { "Ref": "DbSecurityGroup" }
      Tags:
        - Key: "Name"
          Value: { "Fn::Join": ["", [ { "Ref": "AWS::Stackname" }, "-db" ] ] }

  DbSecurityGroup:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: "Todobackend DB Security Group"
      VpcId: { "Ref": "VpcId" }
      SecurityGroupIngress:
        - IpProtocol: "tcp"
          FromPort: "3306"
          ToPort: "3306"
          SourceSecurityGroupId: { "Ref": "EC2InstanceSecurityGroup" }

  DbSubnetGroup:
    Type: "AWS::RDS::DBSubnetGroup"
    Properties:
      DBSubnetGroupDescription: "Todobackend DB Subnet Group"
      SubnetIds: { "Ref": "DbSubnets" }
      Tags:
        - Key: "Name"
          Value: { "Fn::Join": ["", [ { "Ref": "AWS::StackName" }, "-db-subnet-group" ] ] }


  # Configure ELB
  ElasticLoadBalancer:
    Type: "AWS::ElasticLoadBalancing::LoadBalancer"
    Properties:
      CrossZone: "false"
      SecurityGroups: [ { "Ref": "ElbSecurityGroup" } ]
      Listeners:
        - LoadBalancerPort: "80"
          InstancePort: "8000"
          Protocol: "http"
      HealthCheck:
        Target: "HTTP:8000/todos"
        HealthyThreshold: "2"
        UnhealthyThreshold: "10"
        Interval: "30"
        Timeout: "5"
      Subnets: [ { "Ref": "SubnetId" } ]
      Tags:
        - Key: "Name"
          Value: { "Fn::Join": ["", [ { "Ref": "AWS::StackName" }, "-elb" ] ] }

  ElbSecurityGroup:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: "Todobackend ELB Security Group"
      VpcId: { "Ref": "VpcId" }
      SecurityGroupIngress:
        - IpProtocol: "tcp"
          FromPort: "80"
          ToPort: "80"
          CidrIp: "0.0.0.0/0"
      Tags:
        - Key: "Name"
          Value: { "Fn::Join": ["", [ { "Ref": "AWS::StackName" }, "-elb-sg" ] ] }

  # Configure ECS
  EcsCluster:
    Type: "AWS::ECS::EcsCluster"

  TodobackendTaskDefinition:
    Type: "AWS::ECS::TaskDefinition"
    Properties:
      ContainerDefinitions:

        - Name: todobackend
          Image: shamdockerhub/todobackend
          Memory: 450
          Environment:
            - Name: DJANGO_SETTINGS_MODULE
              Value: todobackend.settings.release
            - Name: MYSQL_HOST
              Value: { "Fn::GetAtt": ["DbInstance", "Endpoint.Address"] }
            - Name: MYSQL_USER
              Value: { "Ref": "DbUsername" }
            - Name: MYSQL_PASSWORD
              Value: { "Ref": "DbPassword" }
          MountPoints:
            - ContainerPath: /var/www/todobackend
              SourceVolume: webroot
          Command:
            - uwsgi
            - "--socket /var/www/todobackend/todobackend.sock"
            - "--chmod-socket=666"
            - "--module todobackend.wsgi"
            - "--master"
            - "--die-on-term"

        - Name: nginx
          Image: shamdockerhub/todobackend-nginx
          Memory: 300
          PortMappings:
            - ContainerPort: "8000"
              HostPort: "8000"
          MountPoints:
            - ContainerPath: /var/www/todobackend
              SourceVolume: webroot

      Volumes:
        - Name: webroot
          Host:
            SourcePath: /ecs/webroot

  TodobackendService:
    Type: "AWS::ECS::Service"
    Properties:
      TaskDefinition: { "Ref": "TodobackendTaskDefinition" }
      Cluster: { "Ref": "EcsCluster" }
      LoadBalancers:
        - ContainerName: "nginx"
          ContainerPort: "8000"
          LoadBalancerName: { "Ref": "ElasticLoadBalancer" }
      Role: { "Ref": "EcsServiceRole" }
      DesiredCount: 0

  EcsServiceRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument: {
        "Version": "2012-10-17",
        "Statement": [
          {
            "Effect": "Allow",
            "Principal": { 
              "Service": [ "ecs.amazonaws.com" ] 
            },
            "Action": [ "sts:AssumeRole"]
          }
        ]
      }
      Path: "/"
      ManagePolicyArns:
        - arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceRole

  TodobackendAdhocTaskDefinition: # Application management task
    Type: "AWS::ECS::TaskDefinition"
    Properties:
      ContainerDefinitions:
        - Name: todobackend
          Image: shamdockerhub/todobackend
          Memory: 245
          Environment:
            - Name: DJANGO_SETTINGS_MODULE
              Value: todobackend.settings.release
            - Name: MYSQL_HOST
              Value: { "Fn::GetAtt": ["DbInstance", "Endpoint.Address"] }
            - Name: MYSQL_USER
              Value: { "Ref": "DbUsername" }
            - Name: MYSQL_PASSWORD
              Value: { "Ref": "DbPassword" }
          MountPoints:
            - ContainerPath: /var/www/todobackend
              SourcePath: webroot

      Volumes:
        - Name: webroot
          Host:
            SourcePath: /ecs/webroot


  # Stack outputs
  Outputs:
    ElbDomainName:
      Description: "Public DNS name of Elastic Load Balancer"
      Value: { "Fn::GetAtt": [ "ElasticLoadBalancer", "DNSName" ] }
    EcsCluster:
      Description: "Amazon resource name (ARN) of Todobackend Ecs Cluster"
      Value: { "Ref": "EcsCluster" }
    TodobackendTaskDefinition:
      Description: "Amazon resource name (ARN) of Todobackend Task definition"
      Value: { "Ref": "TodobackendTaskDefinition"}
    TodobackendAdhocTaskDefinition:
      Description: "Amazon resource name(ARN) of Todobackend Adhoc Task Definition"
      Value: { "Ref": "TodobackendAdhocTaskDefinition" }
    TodobackendService:
      Description: "Amazon resource name (ARN) of Todobackend service"
      Value: { "Ref": "TodobackendService" }

---

below is the error from Outputs block:

 Invalid template resource property 'ElbDomainName'

---

We need dns name of elastic load balancer to be part of Outputs block of stack

Why 'ElbDomainName' an invalid property?

Answer 1

The entire Outputs: block is indented a level too far. Outputs: should not be underneath Resources: indentation-wise

Outputs documentation