Open the nodeserver-cf-template.py script.

After the first IAM policy, add the following MonitoringPolicy IAM policy. Simply add the following action to the statement:

t.add_resource(IAMPolicy( 
    "MonitoringPolicy", 
    PolicyName="AllowSendingDataForMonitoring", 
    PolicyDocument=Policy( 
        Statement=[ 
            Statement( 
                Effect=Allow, 
                Action=[ 
                    Action("cloudwatch", "Put*"), 
                    Action("logs", "Create*"), 
                    Action("logs", "Put*"), 
                    Action("logs", "Describe*"), 
                    Action("events", "Put*"), 
                    Action("firehose", "Put*"), 
                    Action("autoscaling", "DescribeAutoScalingInstances"), 
                ], 
                Resource=["*"]) 
        ] 
    ), 
    Roles=[Ref("Role")] 
)) 

Save the file. It should be similar to http://bit.ly/2v3cdeM.

Then, once again, update the stacks:

$ git add nodeserver-cf-template.py
$ git commit -m "Allowing the instance to describe the ASG instances"
$ git push
$ python nodeserver-cf-template.py > nodeserver-cf.template 

$ aws cloudformation update-stack 
      --capabilities CAPABILITY_IAM 
      --stack-name helloworld-staging 
      --template-body file://nodeserver-cf.template 
      --parameters 
          ParameterKey=InstanceType,UsePreviousValue=true 
          ParameterKey=KeyPair,,UsePreviousValue=true 
          ParameterKey=PublicSubnet,,UsePreviousValue=true 
          ParameterKey=ScaleCapacity,,UsePreviousValue=true 
          ParameterKey=VpcId,,UsePreviousValue=true

$ aws cloudformation update-stack 
      --capabilities CAPABILITY_IAM 
      --stack-name helloworld-production 
      --template-body file://nodeserver-cf.template 
      --parameters 
          ParameterKey=InstanceType,UsePreviousValue=true 
          ParameterKey=KeyPair,UsePreviousValue=true 
          ParameterKey=PublicSubnet,UsePreviousValue=true 
          ParameterKey=ScaleCapacity,UsePreviousValue=true 
          ParameterKey=VpcId,UsePreviousValue=true

Next, we are going to create a new role in our Ansible repository to install and configure a tool to emit those metrics.