您可以在模板Parameters的RandomName參數中，設置AssociationProperty為AutoCompleteInput，然后同時設置AssociationPropertyMetadata中的Length、Prefix和CharacterClasses屬性，從而控制隨機字符串的長度。更多信息，請參見AssociationProperty和AssociationPropertyMetadata。

{
  "ROSTemplateFormatVersion": "2015-09-01",
  "Parameters": {
    "RandomName": {
      "Type": "String",
      "Label": {
        "en": "Random Name",
        "zh-cn": "隨機名稱"
      },
      "AssociationProperty": "AutoCompleteInput",
      "AssociationPropertyMetadata": {
        "Length": 5 ,
        "Prefix": "test-ros",
        "CharacterClasses": [
          {
            "Class": "lowercase",
            "min": 1
          }
        ]
      }
    }
  },
  "Outputs": {
    "RandomNameStr": {
      "Value": {
        "Ref": "RandomName"
      }
    }
  }
}

控制臺示例