terraformリソースは、変数に基づいて複数のCloudWatchアラームを作成する必要があります。これはプランで確認されていますが、1つのアラームのみをデプロイします。

テラフォームコード：

resource "aws_cloudwatch_metric_alarm" "disk_percentage_low" {
  for_each                  = toset(var.instance)

  alarm_name                = "disk_percentage_low"  
  comparison_operator       = "LessThanOrEqualToThreshold"  
  evaluation_periods        = "1"                  
  metric_name"LogicalDisk   = % Free Space"   
  namespace                 = "CWAgent"  
  period                    = "60"   
  statistic                 = "Average"            
  threshold                 = "20"
  alarm_description         = "This metric monitors ec2 disk utilization"   
  actions_enabled           = "true"    
  alarm_actions             = [aws_sns_topic.disk_alarm.arn]   
  insufficient_data_actions = []
  
  dimensions = {
    InstanceId   = var.InstanceId
    InstanceType = var.InstanceType
    ImageId      = var.ImageId
    instance     = each.value
    objectname   = var.objectname   
  } 
}

variable "instance" {   
  type = list   
  default = ["E:" , "D:"]
}

これがTerraformプランからの出力です。あなたはそれが例えば2つのCloudWatchのアラームを作成する必要が見ることができるようにE:とD:、私はコンソールに行くときに適用が正常に実行された後、しかし、それは唯一のインスタンスのアラームを作成しますE:

# aws_cloudwatch_metric_alarm.disk_percentage_low["D:"] will be created   
+ resource "aws_cloudwatch_metric_alarm"
"disk_percentage_low" {
  + actions_enabled      = true
  + alarm_actions        = (known after apply)
  + alarm_description    = "This metric monitors ec2 disk utilization"
  + alarm_name           = "disk_percentage_low"
  + arn                  = (known after apply)
  + comparison_operator  = "LessThanOrEqualToThreshold"
  + dimensions                              = {
      + "ImageId"      = "ami-0aac9d7fa83beb6d2"
      + "InstanceId"   = "i-021e580bccd130ac6"
      + "InstanceType" = "t2.micro"
      + "instance"     = "D:"
      + "objectname"   = "LogicalDisk"
    }
  + evaluate_low_sample_count_percentiles = (known after apply)
  + evaluation_periods                    = 1
  + id                                    = (known after apply)
  + metric_name                           = "LogicalDisk % Free Space"
  + namespace                             = "CWAgent"
  + period                                = 60
  + statistic                             = "Average"
  + threshold                             = 20
  + treat_missing_data                    = "missing"
}

# aws_cloudwatch_metric_alarm.disk_percentage_low["E:"] will be created   
+ resource "aws_cloudwatch_metric_alarm"
"disk_percentage_low" {
  + actions_enabled     = true
  + alarm_actions       = (known after apply)
  + alarm_description   = "This metric monitors ec2 disk utilization"
  + alarm_name          = "disk_percentage_low"
  + arn                 = (known after apply)
  + comparison_operator = "LessThanOrEqualToThreshold"
  + dimensions                            = {
      + "ImageId"      = "ami-0aac9d7fa83beb6d2"
      + "InstanceId"   = "i-021e580bccd130ac6"
      + "InstanceType" = "t2.micro"
      + "instance"     = "E:"
      + "objectname"   = "LogicalDisk"
    }
  + evaluate_low_sample_count_percentiles = (known after apply)
  + evaluation_periods                    = 1
  + id                                    = (known after apply)
  + metric_name                           = "LogicalDisk % Free Space"
  + namespace                             = "CWAgent"
  + period                                = 60
  + statistic                             = "Average"
  + threshold                             = 20
  + treat_missing_data                    = "missing"
}