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

The ALIYUN::ROS::Stack type nests a stack as a resource in a top-level template.

You can add output values from a nested stack contained within the template. You can use the Fn::GetAtt function in combination with the logical name of the nested stack and the names of output values in the nested stack in the Outputs.NestedStackOutputName format.

Notice We recommend that you run updates to nested stacks from the parent stack.

When you apply template changes to update a top-level stack, ROS updates the top-level stack and initiates an update to its nested stacks. ROS updates the resources of modified nested stacks, but does not update the resources of unmodified nested stacks.

Syntax

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

Properties

Property Type Required Editable Description Constraint
TemplateURL String No Yes

The URL of the file that contains the template body.

The template body file 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 located in an HTTP or HTTPS web server or an 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 or TemplateBody parameters. If both of 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 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 and TemplateBody parameters. If both of the parameters are specified, the TemplateBody parameter takes precedence.

TimeoutMins Number No Yes The length of time that ROS will wait for the nested stack to be created or updated. Unit: minutes.

Default value: 60.

Parameters Map No Yes A set of value pairs that represent the parameters passed to 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.

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 VPC, a VSwitch, and a security group in an inner-level 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"
            ]
          }
        }
      }
    }
  • The following code provides an example on an outer-level 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"
          }
        }
      }
    }