ALIYUN::ROS::Stack is used to create a nested stack. You can have a maximum of five nested levels.

Nested stacks can themselves contain other nested stacks. This results in a hierarchy of stacks. The root stack is the top-level stack to which all the nested stacks belong. The template of the root stack is called the top-level template. The ALIYUN::ROS::Stack type nests a stack as a resource in a top-level template.

In a nested stack template, you can use outputs from one stack as inputs to another stack. To obtain the output of the nested stack, you can use the Fn::GetAtt function and set the function parameters to the name of the nested stack and the output value in the Outputs.NestedStackOutputName format. For more information, see Use nested stacks.

Syntax

{
  "Type": "ALIYUN::ROS::Stack",
  "Properties": {
    "TemplateURL": String,
    "TemplateBody": String,
    "TemplateId": String,
    "TemplateVersion": String,
    "TimeoutMins": Number,
    "Parameters": Map,
    "ResourceGroupId": String
  }
}

Properties

Property Type Required Editable Description Constraint
TemplateURL String No Yes The URL of the file that contains the template body. The file that contains the template body can be up to 524,288 bytes in size. The URL can be up to 1,024 bytes in length.

The URL must point to a template that is located in an HTTP or HTTPS web server or an Object Storage Service (OSS) bucket. Example: oss://ros/template/demo or oss://ros/template/demo?RegionId=cn-hangzhou.

If the region of the OSS bucket is not specified, the RegionId parameter value is used by default.

You must specify one of the TemplateURL, TemplateBody, and TemplateId parameters. If all the parameters are specified, the TemplateBody parameter takes precedence.

TemplateBody Map No Yes The structure that contains the template body, which is used to facilitate the delivery of the template.

The content is raw data. Functions in the template body are not resolved in the parent stack.

You must specify one of the TemplateURL, TemplateBody, and TemplateId parameters. If all the parameters are specified, the TemplateBody parameter takes precedence.

TemplateId String No Yes The ID of the template.

You must specify one of the TemplateURL, TemplateBody, and TemplateId parameters. If all the parameters are specified, the TemplateBody parameter takes precedence.

TemplateVersion String No Yes The name of the template version. None
TimeoutMins Number No Yes The timeout period for creating or updating a stack. Unit: minutes.

Default value: 60.

Parameters Map No Yes A set of key-value pairs that represent the parameters passed to Resource Orchestration Service (ROS) when the nested stack is created. Each parameter has a key corresponding to a parameter name defined in the template of the nested stack and a value representing the value that you want to set for the parameter. This parameter is required if the nested stack requires input parameters.
ResourceGroupId String No No The ID of the resource group. None

Response parameters

Fn::GetAtt

You can use the following code to obtain the output of the nested stack:

{
  "Fn::GetAtt": [
    "<nested_stack>",
    "Outputs.<nested_stack_output_name>"
  ]
}

When you use Ref to reference resources in a nested stack, the Alibaba Cloud Resource Name (ARN) of the nested stack is returned. Example: arn:acs:ros::cn-hangzhou:12345****:stacks/test-nested-stack-Demo-jzkyq7mn****/e71c1e04-1a57-46fc-b9a4-cf7ce0d3****.

Examples

  • The following code provides an example on how to create a virtual private cloud (VPC), a vSwitch, and a security group in a nested stack and save the output results to the oss://ros/template/vpc.txt directory:
    {
      "ROSTemplateFormatVersion": "2015-09-01",
      "Description": "One VPC, VSwitch, security group.",
      "Parameters": {
        "ZoneId": {
          "Type": "String",
          "Description": "The available zone"
        },
        "SecurityGroupName": {
          "Type": "String",
          "Description": "The security group name",
          "Default": "my-sg-name"
        },
        "VpcName": {
          "Type": "String",
          "Description": "The VPC name",
          "MinLength": 2,
          "MaxLength": 128,
          "ConstraintDescription": "[2, 128] English or Chinese letters",
          "Default": "my-vpc-name"
        },
        "VpcCidrBlock": {
          "Type": "String",
          "AllowedValues": [
            "192.168.0.0/16",
            "172.16.0.0/12",
            "10.0.0.0/8"
          ],
          "Default": "10.0.0.0/8"
        },
        "VSwitchCidrBlock": {
          "Type": "String",
          "Description": "The VSwitch subnet which must be within VPC",
          "Default": "10.0.10.0/24"
        },
        "UpdateVersion": {
          "Type": "Number",
          "Default": 0
        }
      },
      "Resources": {
        "Vpc": {
          "Type": "ALIYUN::ECS::VPC",
          "Properties": {
            "CidrBlock": {
              "Ref": "VpcCidrBlock"
            },
            "VpcName": {
              "Ref": "VpcName"
            }
          }
        },
        "VSwitch": {
          "Type": "ALIYUN::ECS::VSwitch",
          "Properties": {
            "CidrBlock": {
              "Ref": "VSwitchCidrBlock"
            },
            "ZoneId": {
              "Ref": "ZoneId"
            },
            "VpcId": {
              "Fn::GetAtt": [
                "Vpc",
                "VpcId"
              ]
            }
          }
        },
        "SecurityGroup": {
          "Type": "ALIYUN::ECS::SecurityGroup",
          "Properties": {
            "SecurityGroupName": {
              "Ref": "SecurityGroupName"
            },
            "VpcId": {
              "Ref": "Vpc"
            }
          }
        },
        "WaitConditionHandle": {
          "Type": "ALIYUN::ROS::WaitConditionHandle",
          "Properties": {
            "UpdateVersion": {
              "Ref": "UpdateVersion"
            }
          }
        }
      },
      "Outputs": {
        "SecurityGroupId": {
          "Value": {
            "Fn::GetAtt": [
              "SecurityGroup",
              "SecurityGroupId"
            ]
          }
        },
        "VpcId": {
          "Value": {
            "Fn::GetAtt": [
              "Vpc",
              "VpcId"
            ]
          }
        },
        "VSwitchId": {
          "Value": {
            "Fn::GetAtt": [
              "VSwitch",
              "VSwitchId"
            ]
          }
        }
      }
    }
  • Example of a parent stack
    {
      "ROSTemplateFormatVersion": "2015-09-01",
      "Description": "One ECS instance.",
      "Parameters": {
        "ImageId": {
          "Default": "centos_7",
          "Type": "String",
          "Description": "Image Id, represents the image resource to startup the ECS instance"
        },
        "InstanceType": {
          "Type": "String",
          "Description": "The ECS instance type,",
          "Default": "ecs.xn4.small"
        },
        "ZoneId": {
          "Type": "String",
          "Description": "The available zone "
        },
        "InstanceChargeType": {
          "Type": "String",
          "AllowedValues": [
            "PrePaid",
            "PostPaid"
          ],
          "Default": "PostPaid",
          "Description": "The instance charge type"
        },
        "SecurityGroupName": {
          "Type": "String",
          "Description": "The security group name",
          "Default": "my-sg-name"
        },
        "NetworkInterfaceName": {
          "Type": "String",
          "Description": "The Network interface name",
          "Default": "my-eni-name"
        },
        "VpcName": {
          "Type": "String",
          "Description": "The VPC name",
          "MinLength": 2,
          "MaxLength": 128,
          "ConstraintDescription": "[2, 128] English or Chinese letters",
          "Default": "my-vpc-name"
        },
        "IoOptimized": {
          "AllowedValues": [
            "none",
            "optimized"
          ],
          "Description": "IO optimized, optimized is for the IO optimized instance type",
          "Type": "String",
          "Default": "optimized"
        },
        "SystemDiskCategory": {
          "AllowedValues": [
            "cloud",
            "cloud_efficiency",
            "cloud_ssd"
          ],
          "Description": "System disk category: average cloud disk(cloud), efficient cloud disk(cloud_efficiency) or SSD cloud disk(cloud_ssd)",
          "Type": "String",
          "Default": "cloud_ssd"
        },
        "VpcCidrBlock": {
          "Type": "String",
          "AllowedValues": [
            "192.168.0.0/16",
            "172.16.0.0/12",
            "10.0.0.0/8"
          ],
          "Default": "10.0.0.0/8"
        },
        "VSwitchCidrBlock": {
          "Type": "String",
          "Description": "The VSwitch subnet which must be within VPC",
          "Default": "10.0.10.0/24"
        },
        "UpdateVersion": {
          "Type": "Number",
          "Default": 0
        }
      },
      "Resources": {
        "NetworkStack": {
          "Type": "ALIYUN::ROS::Stack",
          "Properties": {
            "TemplateURL": "oss://ros/template/vpc.txt",
            "TimeoutMins": 5,
            "Parameters": {
              "ZoneId": {
                "Ref": "ZoneId"
              },
              "SecurityGroupName": {
                "Ref": "SecurityGroupName"
              },
              "VpcName": {
                "Ref": "VpcName"
              },
              "VpcCidrBlock": {
                "Ref": "VpcCidrBlock"
              },
              "VSwitchCidrBlock": {
                "Ref": "VSwitchCidrBlock"
              },
              "UpdateVersion": {
                "Ref": "UpdateVersion"
              }
            }
          }
        },
        "WebServer": {
          "Type": "ALIYUN::ECS::Instance",
          "Properties": {
            "ImageId": {
              "Ref": "ImageId"
            },
            "InstanceType": {
              "Ref": "InstanceType"
            },
            "InstanceChargeType": {
              "Ref": "InstanceChargeType"
            },
            "SecurityGroupId": {
              "Fn::GetAtt": [
                "NetworkStack",
                "Outputs.SecurityGroupId"
              ]
            },
            "VpcId": {
              "Fn::GetAtt": [
                "NetworkStack",
                "Outputs.VpcId"
              ]
            },
            "VSwitchId": {
              "Fn::GetAtt": [
                "NetworkStack",
                "Outputs.VSwitchId"
              ]
            },
            "IoOptimized": {
              "Ref": "IoOptimized"
            },
            "ZoneId": {
              "Ref": "ZoneId"
            },
            "SystemDisk_Category": {
              "Ref": "SystemDiskCategory"
            },
            "DiskMappings": [
              {
                "Category": "cloud_ssd",
                "Size": 20
              }
            ]
          }
        }
      },
      "Outputs": {
        "InstanceId": {
          "Value": {
            "Fn::GetAtt": [
              "WebServer",
              "InstanceId"
            ]
          }
        },
        "PublicIp": {
          "Value": {
            "Fn::GetAtt": [
              "WebServer",
              "PublicIp"
            ]
          }
        },
        "SecurityGroupId": {
          "Value": {
            "Fn::GetAtt": [
              "NetworkStack",
              "Outputs.SecurityGroupId"
            ]
          }
        },
        "VpcId": {
          "Value": {
            "Fn::GetAtt": [
              "NetworkStack",
              "Outputs.VpcId"
            ]
          }
        },
        "VSwitchId": {
          "Value": {
            "Fn::GetAtt": [
              "NetworkStack",
              "Outputs.VSwitchId"
            ]
          }
        },
        "NetworkStackArn": {
          "Value": {
            "Ref": "NetworkStack"
          }
        }
      }
    }

For more examples, see MongoDBInstance.json and MongoDBInstance.yml.