How to use multiple separate dimensions for custom cloudwatch metrics?

Question

With this we can configure dimensions for our custom metric.

{
   "metrics":{
      "append_dimensions":{
         "AutoScalingGroupName":"${!aws:AutoScalingGroupName}",
         "ImageId":"${!aws:ImageId}",
         "InstanceId":"${!aws:InstanceId}",
         "InstanceType":"${!aws:InstanceType}"
      },
      "metrics_collected":{
         "mem":{
            "measurement":[
               "mem_used_percent"
            ]
         },
         "swap":{
            "measurement":[
               "swap_used_percent"
            ]
         }
      }
   }
}

This gives something like:

Now I try to create an alarm for the dimension autoscaling group:

  MemoryAlarmHigh:
   Type: AWS::CloudWatch::Alarm
   Properties:
     EvaluationPeriods: '1'
     Statistic: Average
     Threshold: '70'
     AlarmDescription: Go in Alarm is memory is higher than 70% for 60 seconds
     Period: '60'
     AlarmActions:
     - Ref: ScaleUpPolicy
     Namespace: CWAgent
     Dimensions:
     - Name: AutoScalingGroupName
       Value: !Ref ASG
     ComparisonOperator: GreaterThanThreshold
     MetricName: xxx

This does not work. I get insufficient data. Now when I use

            {
              "metrics": {
                "append_dimensions": {
                  "AutoScalingGroupName": "${!aws:AutoScalingGroupName}"
                },
                "metrics_collected": {
                  "mem": {
                    "measurement": [
                      "mem_used_percent"
                    ]
                  }
                }
              }
            }

I get:

And the alarm works now. But I want to use multiple dimensions but use them separately (like in the EC2 namespace) so I can use my alarm.

How can I do this?

Answer 1

Try setting aggregation_dimensions.

Like this:

{
   "metrics":{
      "append_dimensions":{
         "AutoScalingGroupName":"${!aws:AutoScalingGroupName}",
         "ImageId":"${!aws:ImageId}",
         "InstanceId":"${!aws:InstanceId}",
         "InstanceType":"${!aws:InstanceType}"
      },
      "aggregation_dimensions" : [["AutoScalingGroupName"]],
      "metrics_collected":{
         "mem":{
            "measurement":[
               "mem_used_percent"
            ]
         },
         "swap":{
            "measurement":[
               "swap_used_percent"
            ]
         }
      }
   }
}

https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Agent-Configuration-File-Details.html#CloudWatch-Agent-Configuration-File-Metricssection