This topic describes the data structures of four change sets, which are Change, ResourceChange, ResourceChangeDetail, and ResourceTargetDefinition.

Change

Parameter Type Description
ResourceChange Structure The resource that ROS will change and the operation that ROS will perform.
Type String The type of the object to which the changes are made. Only Resource is supported.

ResourceChange

Parameter Type Description
Action String The operation that you want to perform. Valid values:
  • Add: creates resources.
  • Modify: modifies resources.
  • Remove: releases resources.
Details Array The detailed changes that are made to resources. This parameter is displayed only when the Action parameter is set to Modify.
LogicalResourceId String The logical ID of the resource as defined in the template.
PhysicalResourceId String The physical ID of the resource. When the Action parameter is set to Add, no physical ID is available because the resource has not been created.
Replacement String Specifies whether ROS replaces resources by creating new resources and deleting the original ones when the Action parameter is set to Modify.
Valid values:
  • True: ROS replaces resources by creating new resources and deleting the original ones.
  • False: ROS does not replace resources by creating new resources and deleting the original ones.
  • Conditional: ROS may replace resources by creating new resources and deleting the original ones.
The value of this parameter depends on the RequiresRecreation value in the ResourceTargetDefinition structure.
  • If the RequiresRecreation parameter is set to Always and the Evaluation parameter is set to Static, the value of the Replacement parameter is True.
  • If the RequiresRecreation parameter is set to Always and the Evaluation parameter is set to Dynamic, the value of the Replacement parameter is Conditional.
  • If there are multiple changes on a single resource and each change has a different value for the RequiresRecreation parameter, the value of the Replacement parameter depends on the change operation that has the greatest impact. The impact of change operations is in the following descending order: Always, Conditional, Never.
ResourceType String The type of the ROS resource.
Scope String array The parameter that triggers updates when the Action parameter is set to Modify. Valid values:
  • Properties: The Properties parameter of the resource is updated
  • Metadata: The Metadata parameter of the resource is updated.
  • DeletionPolicy: The DeletionPolicy parameter of the resource is updated.

ResourceChangeDetail

Parameter Type Description
ChangeSource String The reason why an update is triggered. Valid values:
  • ResourceReference: The referenced physical ID of another resource may be changed.
  • ParameterReference: The referenced parameter is changed.
  • ResourceAttribute: The referenced output attribute of another resource may be changed.
  • DirectModification: The template is modified.
  • Automatic: If the nested stack created through the ALIYUN::ROS::Stack resource has not been modified, ROS sets the ChangeSource parameter to Automatic. This is because the template of the nested stack may have already been changed. ROS does not update the nested stack template before you update the parent stack.
  • System: Specific conditions or internal mechanisms can trigger updates even if the input values for some resources have not been changed. Example: ALIYUN::ROS::WaitConditionHandle.
CausingEntity String The objects associated with the ChangeSource parameter. The mappings are as follows:
  • When the ChangeSource parameter is set to ResourceReference, the CausingEntity value indicates the resource name.
  • When the ChangeSource parameter is set to ParameterReference, the CausingEntity value indicates the parameter name.
  • When the ChangeSource parameter is set to ResourceAttribute, the CausingEntity value indicates the attribute name, in the "resource name.attribute name" format.
  • When the ChangeSource parameter is set to DirectModification, the CausingEntity parameter is empty by default.
  • When the ChangeSource parameter is set to Automatic, the CausingEntity value indicates the resource name.
  • When the ChangeSource parameter is set to System, the CausingEntity value indicates the resource name.
Evaluation String Specifies whether ROS can determine the target values and whether original values are changed to target values before a change set is executed. Valid values:
  • Static

    When this parameter is set to Static, ROS can determine the target values and original values are changed to target values.

  • Dynamic

    When this parameter is set to Dynamic, ROS cannot determine the target values. When ROS updates the stack, the target values depend on the results of internal functions such as Ref or Fn::GetAtt.

Target Structure The detailed information about parameters that trigger updates.

ResourceTargetDefinition

Parameter Type Description
Attribute String The parameter that triggers updates. Valid values:
  • Properties: The Properties parameter of the resource is updated.
  • Metadata: The Metadata parameter of the resource is updated.
  • DeletionPolicy: The DeletionPolicy parameter of the resource is updated.
Name String When the Attribute parameter is set to Properties, this parameter takes effect, and the value specifies the specific attribute name. Otherwise, the value is set to null.
RequiresRecreation String Whether attribute changes lead to resource re-creation when the Attribute parameter is set to Properties. Valid values:
  • Never: Attribute changes do not lead to resource re-creation.
  • Conditionally: Attribute changes may lead to resource re-creation.
  • Always: Attribute changes lead to resource re-creation.