You can specify DataSource to query the resource data of an Alibaba Cloud service. Data source resources can be referenced by resources and output items. Data source resources and regular resources can be used in different scenarios. Data source resources provide the same features, such as references, dependencies, and updates, as regular resources.

Scenarios

  • Use filtered values as input properties to create a new resource

    Resource Orchestration Service (ROS) filters the values of data source resources based on specified conditions, and uses the filtered values as input properties to create a new resource.

  • Display resource details on the Outputs tab

    After you specify a data source resource in the Resources section of a template, you can reference the data source resource in the Outputs section of the template. Then, the ROS console can display the details of the resource on the Outputs tab.

Use filtered values as input properties to create a new resource

ROS filters the values of data source resources based on specified conditions, and uses the filtered values as input properties to create a new resource.

The following template shows how to specify the Parameters and Resources sections to filter the values of parameters and resources. Then, ROS uses the filtered values as input properties to create an Elastic Compute Service (ECS) instance. You specify the following properties to set filter conditions:

  • Cores and Memory: Specify the properties to query available ECS instance specifications. By default, ROS uses the first instance specifications to create the ECS instance.
  • ImageName: Specify the property to query available images. By default, ROS uses the ID of the first image to create the ECS instance. 
ROSTemplateFormatVersion: '2015-09-01'
Parameters:
  ZoneId:
    Type: String
    AssociationProperty: ALIYUN::ECS::ZoneId
  VpcId:
    Type: String
    AssociationProperty: ALIYUN::ECS::VPC::VPCId
  VSwitchId:
    Type: String
    AssociationProperty: ALIYUN::ECS::VSwitch::VSwitchId
    AssociationPropertyMetadata:
      VpcId: ${VpcId}
      ZoneId: ${ZoneId}
  SecurityGroupId:
    Type: String
    AssociationProperty: ALIYUN::ECS::SecurityGroup::SecurityGroupId
    AssociationPropertyMetadata:
      VpcId: ${VpcId}
Resources:
  DS-RecommendInstanceTypes:
    Type: DATASOURCE::ECS::RecommendInstanceTypes
    Properties:
      Cores: 1
      Memory: 1
  DS-Images:
    Type: DATASOURCE::ECS::Images
    Properties:
      ImageName: CentOS8*
      InstanceType:
        Fn::Select:
          - 0
          - Ref: DS-RecommendInstanceTypes
  Instance:
    Type: ALIYUN::ECS::Instance
    Properties:
      InstanceName: MyInstance
      ImageId:
        Fn::Select:
          - 0
          - Ref: DS-Images
      InstanceType:
        Fn::Select:
          - 0
          - Ref: DS-RecommendInstanceTypes
      ZoneId:
        Ref: ZoneId
      VSwitchId:
        Ref: VSwitchId
      SecurityGroupId:
        Ref: SecurityGroupId
      SystemDiskCategory: cloud_efficiency
Outputs:
  InstanceId:
    Value:
      Ref: Instance

The template contains the following information:

  • In the Parameters section, you specify the following parameters: ZoneId, VpcId, VSwitchId, and SecurityGroupId. You specify AssociationProperty for each parameter. This way, you can view the values of the parameters and select a value for each parameter in the parameter settings section in the ROS console.
  • In the Resources section, you specify the following data source resources and regular resource:
    • DS-RecommendInstanceTypes: The logical ID of a data source resource. You set the filter conditions to 1 core and 1 GB memory to query available instance specifications.
    • DS-Images: The logical ID of a data source resource. You set InstanceType to { "Fn::Select": [0, { "Ref": "DS-RecommendInstanceTypes" }] to use the first ECS instance specifications of available specifications. You also set ImageName to a value prefixed with CentOS to query available images.
    • Instance: The logical ID of a regular resource. ROS uses the first instance specifications and image ID as input properties to create the ECS instance.
  • In the Outputs section, you specify InstanceId.

Display resource details on the Outputs tab

After you specify a data source resource in the Resources section of a template, you can reference the data source resource in the Outputs section of the template. Then, the ROS console can display the details of the resource on the Outputs tab.

The following template shows how to specify properties to create a virtual private cloud (VPC), and specify the VPC as a data source resource. This way, ROS can query the details of the VPC and display the details on the Outputs tab. 

ROSTemplateFormatVersion: '2015-09-01'
Resources:
  Vpc:
    Type: ALIYUN::ECS::VPC
    Properties:
      VpcName: MyVpc
      CidrBlock: 172.16.0.0/12
  DS-Vpcs:
    Type: DATASOURCE::VPC::Vpcs
    Properties:
      VpcIds:
        - Ref: Vpc
Outputs:
  VpcData:
    Value:
      Fn::Select:
        - 0
        - Fn::GetAtt:
            - DS-Vpcs
            - Vpcs

The template contains the following information:

  • In the Resources section, you specify the following regular resource and data source resource:
    • Vpc: The logical ID of a regular resource. You specify VpcName and CidrBlock to create the VPC.
    • DS-Vpcs: The logical ID of a data source resource. ROS uses the ID of the created VPC as an input property to query the details of the VPC.
  • In the Outputs section, you specify ["DS-Vpcs", "Vpcs"] for VpcData to query the first value.