You can call this operation to preview the stack to be created by using a specified template.

Debugging

OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer. OpenAPI Explorer dynamically generates the sample code of the operation for different SDKs.

Request parameters

Parameter Type Required Example Description
Action String Yes PreviewStack

The operation that you want to perform. Set the value to PreviewStack.

Parameters.N.ParameterKey String Yes InstanceType

The key of parameter N. If the key and value of the parameter are not specified, the key and value in the template are used by default. Maximum value of N: 200.

Note Parameters is an optional parameter. If you specify Parameters, you must specify Parameters.N.ParameterKey.
Parameters.N.ParameterValue String Yes ecs.cm4.6xlarge

The value of parameter N. Maximum value of N: 200.

Note Parameters is an optional parameter. If you specify Parameters, you must specify Parameters.N.ParameterValue.
RegionId String Yes cn-beijing

The region ID of the stack. You can call the DescribeRegions operation to query the most recent region list.

StackName String Yes MyStack

The name of the stack.

The name can be up to 255 characters in length and can contain digits, letters, hyphens (-), and underscores (_). It must start with a digit or letter.

DisableRollback Boolean No false

Specifies whether to disable rollback on stack creation failure. Valid values:

  • true: disables rollback on stack creation failure.
  • false: enables rollback on stack creation failure.
TimeoutInMinutes Long No 10

The timeout period that is specified for the stack creation request.

Unit: minutes.

Default value: 60.

TemplateBody String No {"ROSTemplateFormatVersion": "2015-09-01" }

The structure that contains the template body. The template body must be 1 to 524,288 bytes in length. If the length of the template body is longer than required, we recommend that you add parameters to the HTTP POST request body to avoid request failures due to excessive length of URLs.

Note You must specify one of the TemplateBody and TemplateURL parameters, but you cannot specify both of them.
StackPolicyURL String No oss://ros-stack-policy/demo

The URL for the file that contains the stack policy. The URL must point to a policy located in an HTTP or HTTPS web server or an Alibaba Cloud OSS bucket. Examples: oss://ros/stack-policy/demo and oss://ros/stack-policy/demo?RegionId=cn-hangzhou. The policy can be up to 16,384 bytes in length and the URL can be up to 1,350 bytes in length. If the region of the OSS bucket is not specified, the RegionId parameter value is used by default.

Note You must specify one of the StackPolicyBody and StackPolicyURL parameters, but you cannot specify both of them.
StackPolicyBody String No {"Statement": [{"Action": "Update:*", "Resource": "*", "Effect": "Allow", "Principal": "*"}]}

The structure that contains the stack policy body. The stack policy body must be 1 to 16,384 bytes in length.

Note You must specify one of the StackPolicyBody and StackPolicyURL parameters, but you cannot specify both of them.
ClientToken String No 123e4567-e89b-12d3-a456-42665544****

The client token that is used to ensure the idempotence of the request. You can use the client to generate the value, but you must ensure that it is unique among different requests.

The token can be up to 64 characters in length, and can contain letters, digits, hyphens (-), and underscores (_).

For more information, see How to ensure idempotence.

TemplateURL String No oss://ros-template/demo

The URL for the file that contains the template body. The URL must point to a template located in an HTTP or HTTPS web server or an Alibaba Cloud OSS bucket. Examples: oss://ros/template/demo and oss://ros/template/demo?RegionId=cn-hangzhou. The template can be up to 524,288 bytes in length. If the region of the OSS bucket is not specified, the RegionId parameter value is used by default.

Note You must specify one of the TemplateBody and TemplateURL parameters, but you cannot specify both of them.

Response parameters

Parameter Type Example Description
RequestId String B288A0BE-D927-4888-B0F7-B35EF84B6E6F

The ID of the request.

Stack Struct

The stack information.

Description String One ECS instance.

The description of the stack.

DisableRollback Boolean false

Indicates whether rollback is disabled.

Parameters Array

The parameters of the stack.

ParameterKey String SystemDiskCategory

The key of the parameter.

ParameterValue String cloud_ssd

The value of the parameter.

RegionId String cn-beijing

The region ID of the stack.

Resources Array

The list of resources in the stack.

Description String ECS instance.

The description of the resource.

LogicalResourceId String WebServer

The logical resource ID.

Properties Map { "DiskMappings": [ { "Category": "cloud_ssd", "Size": "20" } ], "SystemDisk_Category": "cloud_ssd", "InstanceChargeType": "PostPaid", "AutoRenew": "False", "WillReplace": true, "ImageId": "centos_7", "InstanceType": "ecs.g6.large", "AllocatePublicIP": true, "AutoRenewPeriod": 1, "IoOptimized": "optimized", "ZoneId": "cn-beijing-g", "VSwitchId": "", "SecurityGroupId": "", "Period": 1, "InternetChargeType": "PayByTraffic", "SystemDiskCategory": "cloud_efficiency", "InternetMaxBandwidthOut": 1, "VpcId": "", "InternetMaxBandwidthIn": 200, "PeriodUnit": "Month" }

The properties of the resource.

RequiredBy List ["Resource1", "Resource2"]

The resources that are dependent on the stack.

ResourceType String ALIYUN::ECS::Instance

The type of the resource.

Stack Map {}

The information of the nested stacks. The data structure of this parameter is the same as that of the entire responses.

StackName String MyStack

The name of the stack.

StackPolicyBody Map { "Statement": [ { "Action": "Update:*", "Resource": "*", "Effect": "Allow", "Principal": "*" }, { "Action": "Update:*", "Resource": "LogicalResourceId/apple1", "Effect": "Deny", "Principal": "*" } ] }

The stack policy.

TemplateDescription String One ECS instance.

The description of the template.

TimeoutInMinutes Integer 10

The timeout period.

Unit: minutes.

Examples

Sample requests

http(s)://ros.aliyuncs.com/? Action=PreviewStack
&RegionId=cn-beijing
&Parameters.1.ParameterValue=ecs.cm4.6xlarge
&Parameters.1.ParameterKey=InstanceType
&StackName=MyStack
&TimeoutInMinutes=10
&<Common request parameters>

Sample success responses

XML format

<PreviewStackResponse>
          <Stack>
                <Description>No description</Description>
                <DisableRollback>true</DisableRollback>
                <Parameters>
                      <ParameterKey>UpdateVersion</ParameterKey>
                      <ParameterValue>1</ParameterValue>
                </Parameters>
                <RegionId>cn-beijing</RegionId>
                <Resources>
                      <Description></Description>
                      <LogicalResourceId>WaitConditionHandle</LogicalResourceId>
                      <Properties>
                            <Count>-1</Count>
                            <Mode>Full</Mode>
                            <UpdateVersion>1</UpdateVersion>
                      </Properties>
                      <ResourceType>ALIYUN::ROS::WaitConditionHandle</ResourceType>
                </Resources>
                <Resources>
                      <Description></Description>
                      <LogicalResourceId>nested</LogicalResourceId>
                      <Properties>
                            <Parameters></Parameters>
                            <TemplateURL>oss://nested-stack/test/demo</TemplateURL>
                            <TimeoutMins>16</TimeoutMins>
                      </Properties>
                      <ResourceType>ALIYUN::ROS::Stack</ResourceType>
                      <Stack>
                            <Description>No description</Description>
                            <DisableRollback>true</DisableRollback>
                            <Parameters>
                                  <ParameterKey>ALIYUN::AccountId</ParameterKey>
                                  <ParameterValue>1666666****</ParameterValue>
                            </Parameters>
                            <Parameters>
                                  <ParameterKey>ALIYUN::NoValue</ParameterKey>
                                  <ParameterValue>None</ParameterValue>
                            </Parameters>
                            <Parameters>
                                  <ParameterKey>ALIYUN::Region</ParameterKey>
                                  <ParameterValue>cn-beijing</ParameterValue>
                            </Parameters>
                            <Parameters>
                                  <ParameterKey>ALIYUN::StackId</ParameterKey>
                                  <ParameterValue>None</ParameterValue>
                            </Parameters>
                            <Parameters>
                                  <ParameterKey>ALIYUN::StackName</ParameterKey>
                                  <ParameterValue>test-preview-stack-complex-nested</ParameterValue>
                            </Parameters>
                            <RegionId>cn-beijing</RegionId>
                            <Resources>
                                  <Description></Description>
                                  <LogicalResourceId>WaitConditionHandle</LogicalResourceId>
                                  <Properties>
                                        <Count>-1</Count>
                                        <Mode>Full</Mode>
                                        <UpdateVersion>1</UpdateVersion>
                                  </Properties>
                                  <ResourceType>ALIYUN::ROS::WaitConditionHandle</ResourceType>
                            </Resources>
                            <StackName>test-preview-stack-complex-nested</StackName>
                            <StackPolicyBody>
                                  <Statement>
                                        <Action>Update:*</Action>
                                        <Effect>Allow</Effect>
                                        <Principal>*</Principal>
                                        <Resource>*</Resource>
                                  </Statement>
                                  <Statement>
                                        <Action>Update:*</Action>
                                        <Effect>Deny</Effect>
                                        <Principal>*</Principal>
                                        <Resource>LogicalResourceId/apple1</Resource>
                                  </Statement>
                            </StackPolicyBody>
                            <TemplateDescription>No description</TemplateDescription>
                            <TimeoutInMinutes>12</TimeoutInMinutes>
                      </Stack>
                </Resources>
                <StackName>test-preview-stack-complex</StackName>
                <StackPolicyBody>
                      <Statement>
                            <Action>Update:*</Action>
                            <Effect>Allow</Effect>
                            <Principal>*</Principal>
                            <Resource>*</Resource>
                      </Statement>
                      <Statement>
                            <Action>Update:*</Action>
                            <Effect>Deny</Effect>
                            <Principal>*</Principal>
                            <Resource>LogicalResourceId/apple1</Resource>
                      </Statement>
                </StackPolicyBody>
                <TemplateDescription>No description</TemplateDescription>
                <TimeoutInMinutes>10</TimeoutInMinutes>
          </Stack>
          <RequestId>B288A0BE-D927-4888-B0F7-B35EF84B6E6F</RequestId>
</PreviewStackResponse>

JSON format

{
    "Stack": {
        "Description": "No description",
        "DisableRollback": true,
        "Parameters": [
            {
                "ParameterKey": "UpdateVersion",
                "ParameterValue": "1"
            }
        ],
        "RegionId": "cn-beijing",
        "Resources": [
            {
                "Description": "",
                "LogicalResourceId": "WaitConditionHandle",
                "Properties": {
                    "Count": -1,
                    "Mode": "Full",
                    "UpdateVersion": 1
                },
                "RequiredBy": [],
                "ResourceType": "ALIYUN::ROS::WaitConditionHandle"
            },
            {
                "Description": "",
                "LogicalResourceId": "nested",
                "Properties": {
                    "Parameters": null,
                    "TemplateURL": "oss://nested-stack/test/demo",
                    "TimeoutMins": 16
                },
                "RequiredBy": [],
                "ResourceType": "ALIYUN::ROS::Stack",
                "Stack": {
                    "Description": "No description",
                    "DisableRollback": true,
                    "Parameters": [
                        {
                            "ParameterKey": "ALIYUN::AccountId",
                            "ParameterValue": "1666666****"
                        },
                        {
                            "ParameterKey": "ALIYUN::NoValue",
                            "ParameterValue": "None"
                        },
                        {
                            "ParameterKey": "ALIYUN::Region",
                            "ParameterValue": "cn-beijing"
                        },
                        {
                            "ParameterKey": "ALIYUN::StackId",
                            "ParameterValue": "None"
                        },
                        {
                            "ParameterKey": "ALIYUN::StackName",
                            "ParameterValue": "test-preview-stack-complex-nested"
                        }
                    ],
                    "RegionId": "cn-beijing",
                    "Resources": [
                        {
                            "Description": "",
                            "LogicalResourceId": "WaitConditionHandle",
                            "Properties": {
                                "Count": -1,
                                "Mode": "Full",
                                "UpdateVersion": 1
                            },
                            "RequiredBy": [],
                            "ResourceType": "ALIYUN::ROS::WaitConditionHandle"
                        }
                    ],
                    "StackName": "test-preview-stack-complex-nested",
                    "StackPolicyBody": {
                        "Statement": [
                            {
                                "Action": "Update:*",
                                "Effect": "Allow",
                                "Principal": "*",
                                "Resource": "*"
                            },
                            {
                                "Action": "Update:*",
                                "Effect": "Deny",
                                "Principal": "*",
                                "Resource": "LogicalResourceId/apple1"
                            }
                        ]
                    },
                    "TemplateDescription": "No description",
                    "TimeoutInMinutes": 12
                }
            }
        ],
        "StackName": "test-preview-stack-complex",
        "StackPolicyBody": {
            "Statement": [
                {
                    "Action": "Update:*",
                    "Effect": "Allow",
                    "Principal": "*",
                    "Resource": "*"
                },
                {
                    "Action": "Update:*",
                    "Effect": "Deny",
                    "Principal": "*",
                    "Resource": "LogicalResourceId/apple1"
                }
            ]
        },
        "TemplateDescription": "No description",
        "TimeoutInMinutes": 10
    },
    "RequestId": "B288A0BE-D927-4888-B0F7-B35EF84B6E6F"    
}

Error codes

For a list of error codes, visit the API Error Center.

For more information about errors common to all operations, see Common error codes.

HTTP status code

Error code

Error message

Description

400

CircularDependency

Circular Dependency Found: {reason}.

The error message returned because the template contains a circular dependency. reason indicates the specific reason.

400

InvalidSchema

{reason}.

The error message returned because the template format is invalid. reason indicates the specific reason.

400

InvalidTemplateAttribute

The Referenced Attribute ({resource} {name}) is incorrect.

The error message returned because the resource attribute referenced in the template is incorrect. resource indicates the resource name, and name indicates the attribute name.

400

InvalidTemplatePropertyType

The specified value type of ({resource} {section}) is incorrect.

The error message returned because the type of the resource section defined in the template is incorrect. resource indicates the resource name, and section indicates the section name.

400

InvalidTemplateReference

The specified reference "{name}" (in {referencer}) is incorrect.

The error message returned because the template contains an invalid reference. name indicates the reference name, and referencer indicates the referencer name.

400

InvalidTemplateSection

The template section is invalid: {section}.

The error message returned because the template contains an invalid section. section indicates the section name.

400

InvalidTemplateVersion

The template version is invalid: {reason}.

The error message returned because the template version is incorrect. reason indicates the specific reason.

400

StackValidationFailed

{reason}.

The error message returned because the stack validation failed. reason indicates the specific reason.

400

UnknownUserParameter

The Parameter ({name}) was not defined in template.

The error message returned because the specified parameter is not defined in the template. name indicates the parameter key.

400

UserParameterMissing

The Parameter {name} was not provided.

The error message returned because no value is passed into the specified parameter defined in the template. name indicates the parameter key.

409

StackExists

The Stack ({name}) already exists.

The error message returned because a stack with the same name already exists. name indicates the stack name.