:doc:`CloudFormation <../../cloudformation>` / Client / describe_change_set

*******************
describe_change_set
*******************



.. py:method:: CloudFormation.Client.describe_change_set(**kwargs)

  

  Returns the inputs for the change set and a list of changes that CloudFormation will make if you execute the change set. For more information, see `Update CloudFormation stacks using change sets <https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-changesets.html>`__ in the *CloudFormation User Guide*.

  

  See also: `AWS API Documentation <https://docs.aws.amazon.com/goto/WebAPI/cloudformation-2010-05-15/DescribeChangeSet>`_  


  **Request Syntax**
  ::

    response = client.describe_change_set(
        ChangeSetName='string',
        StackName='string',
        NextToken='string',
        IncludePropertyValues=True|False
    )
    
  :type ChangeSetName: string
  :param ChangeSetName: **[REQUIRED]** 

    The name or Amazon Resource Name (ARN) of the change set that you want to describe.

    

  
  :type StackName: string
  :param StackName: 

    If you specified the name of a change set, specify the stack name or ID (ARN) of the change set you want to describe.

    

  
  :type NextToken: string
  :param NextToken: 

    The token for the next set of items to return. (You received this token from a previous call.)

    

  
  :type IncludePropertyValues: boolean
  :param IncludePropertyValues: 

    If ``true``, the returned changes include detailed changes in the property values.

    

  
  
  :rtype: dict
  :returns: 
    
    **Response Syntax**

    
    ::

      {
          'ChangeSetName': 'string',
          'ChangeSetId': 'string',
          'StackId': 'string',
          'StackName': 'string',
          'Description': 'string',
          'Parameters': [
              {
                  'ParameterKey': 'string',
                  'ParameterValue': 'string',
                  'UsePreviousValue': True|False,
                  'ResolvedValue': 'string'
              },
          ],
          'CreationTime': datetime(2015, 1, 1),
          'ExecutionStatus': 'UNAVAILABLE'|'AVAILABLE'|'EXECUTE_IN_PROGRESS'|'EXECUTE_COMPLETE'|'EXECUTE_FAILED'|'OBSOLETE',
          'Status': 'CREATE_PENDING'|'CREATE_IN_PROGRESS'|'CREATE_COMPLETE'|'DELETE_PENDING'|'DELETE_IN_PROGRESS'|'DELETE_COMPLETE'|'DELETE_FAILED'|'FAILED',
          'StatusReason': 'string',
          'StackDriftStatus': 'DRIFTED'|'IN_SYNC'|'UNKNOWN'|'NOT_CHECKED',
          'NotificationARNs': [
              'string',
          ],
          'RollbackConfiguration': {
              'RollbackTriggers': [
                  {
                      'Arn': 'string',
                      'Type': 'string'
                  },
              ],
              'MonitoringTimeInMinutes': 123
          },
          'Capabilities': [
              'CAPABILITY_IAM'|'CAPABILITY_NAMED_IAM'|'CAPABILITY_AUTO_EXPAND',
          ],
          'Tags': [
              {
                  'Key': 'string',
                  'Value': 'string'
              },
          ],
          'Changes': [
              {
                  'Type': 'Resource',
                  'HookInvocationCount': 123,
                  'ResourceChange': {
                      'PolicyAction': 'Delete'|'Retain'|'Snapshot'|'ReplaceAndDelete'|'ReplaceAndRetain'|'ReplaceAndSnapshot',
                      'Action': 'Add'|'Modify'|'Remove'|'Import'|'Dynamic'|'SyncWithActual',
                      'LogicalResourceId': 'string',
                      'PhysicalResourceId': 'string',
                      'ResourceType': 'string',
                      'Replacement': 'True'|'False'|'Conditional',
                      'Scope': [
                          'Properties'|'Metadata'|'CreationPolicy'|'UpdatePolicy'|'DeletionPolicy'|'UpdateReplacePolicy'|'Tags',
                      ],
                      'ResourceDriftStatus': 'IN_SYNC'|'MODIFIED'|'DELETED'|'NOT_CHECKED'|'UNKNOWN'|'UNSUPPORTED',
                      'ResourceDriftIgnoredAttributes': [
                          {
                              'Path': 'string',
                              'Reason': 'MANAGED_BY_AWS'|'WRITE_ONLY_PROPERTY'
                          },
                      ],
                      'Details': [
                          {
                              'Target': {
                                  'Attribute': 'Properties'|'Metadata'|'CreationPolicy'|'UpdatePolicy'|'DeletionPolicy'|'UpdateReplacePolicy'|'Tags',
                                  'Name': 'string',
                                  'RequiresRecreation': 'Never'|'Conditionally'|'Always',
                                  'Path': 'string',
                                  'BeforeValue': 'string',
                                  'AfterValue': 'string',
                                  'BeforeValueFrom': 'PREVIOUS_DEPLOYMENT_STATE'|'ACTUAL_STATE',
                                  'AfterValueFrom': 'TEMPLATE',
                                  'Drift': {
                                      'PreviousValue': 'string',
                                      'ActualValue': 'string',
                                      'DriftDetectionTimestamp': datetime(2015, 1, 1)
                                  },
                                  'AttributeChangeType': 'Add'|'Remove'|'Modify'|'SyncWithActual'
                              },
                              'Evaluation': 'Static'|'Dynamic',
                              'ChangeSource': 'ResourceReference'|'ParameterReference'|'ResourceAttribute'|'DirectModification'|'Automatic'|'NoModification',
                              'CausingEntity': 'string'
                          },
                      ],
                      'ChangeSetId': 'string',
                      'ModuleInfo': {
                          'TypeHierarchy': 'string',
                          'LogicalIdHierarchy': 'string'
                      },
                      'BeforeContext': 'string',
                      'AfterContext': 'string',
                      'PreviousDeploymentContext': 'string'
                  }
              },
          ],
          'NextToken': 'string',
          'IncludeNestedStacks': True|False,
          'ParentChangeSetId': 'string',
          'RootChangeSetId': 'string',
          'OnStackFailure': 'DO_NOTHING'|'ROLLBACK'|'DELETE',
          'ImportExistingResources': True|False,
          'DeploymentMode': 'REVERT_DRIFT'
      }
      
    **Response Structure**

    

    - *(dict) --* 

      The output for the  DescribeChangeSet action.

      
      

      - **ChangeSetName** *(string) --* 

        The name of the change set.

        
      

      - **ChangeSetId** *(string) --* 

        The Amazon Resource Name (ARN) of the change set.

        
      

      - **StackId** *(string) --* 

        The Amazon Resource Name (ARN) of the stack that's associated with the change set.

        
      

      - **StackName** *(string) --* 

        The name of the stack that's associated with the change set.

        
      

      - **Description** *(string) --* 

        Information about the change set.

        
      

      - **Parameters** *(list) --* 

        A list of ``Parameter`` structures that describes the input parameters and their values used to create the change set. For more information, see the `Parameter <https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_Parameter.html>`__ data type.

        
        

        - *(dict) --* 

          The ``Parameter`` data type.

          
          

          - **ParameterKey** *(string) --* 

            The key associated with the parameter. If you don't specify a key and value for a particular parameter, CloudFormation uses the default value that's specified in your template.

            
          

          - **ParameterValue** *(string) --* 

            The input value associated with the parameter.

            
          

          - **UsePreviousValue** *(boolean) --* 

            During a stack update, use the existing parameter value that the stack is using for a given parameter key. If you specify ``true``, do not specify a parameter value.

            
          

          - **ResolvedValue** *(string) --* 

            Read-only. The value that corresponds to a Systems Manager parameter key. This field is returned only for Systems Manager parameter types in the template. For more information, see `Specify existing resources at runtime with CloudFormation-supplied parameter types <https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cloudformation-supplied-parameter-types.html>`__ in the *CloudFormation User Guide*.

            
      
    
      

      - **CreationTime** *(datetime) --* 

        The start time when the change set was created, in UTC.

        
      

      - **ExecutionStatus** *(string) --* 

        If the change set execution status is ``AVAILABLE``, you can execute the change set. If you can't execute the change set, the status indicates why. For example, a change set might be in an ``UNAVAILABLE`` state because CloudFormation is still creating it or in an ``OBSOLETE`` state because the stack was already updated.

        
      

      - **Status** *(string) --* 

        The current status of the change set, such as ``CREATE_PENDING``, ``CREATE_COMPLETE``, or ``FAILED``.

        
      

      - **StatusReason** *(string) --* 

        A description of the change set's status. For example, if your attempt to create a change set failed, CloudFormation shows the error message.

        
      

      - **StackDriftStatus** *(string) --* 

        The drift status of the stack when the change set was created. Valid values:

         

        
        * ``DRIFTED`` – The stack has drifted from its last deployment.
         
        * ``IN_SYNC`` – The stack is in sync with its last deployment.
         
        * ``NOT_CHECKED`` – CloudFormation doesn’t currently return this value.
         
        * ``UNKNOWN`` – The drift status could not be determined.
        

         

        Only present for drift-aware change sets.

        
      

      - **NotificationARNs** *(list) --* 

        The ARNs of the Amazon SNS topics that will be associated with the stack if you execute the change set.

        
        

        - *(string) --* 
    
      

      - **RollbackConfiguration** *(dict) --* 

        The rollback triggers for CloudFormation to monitor during stack creation and updating operations, and for the specified monitoring period afterwards.

        
        

        - **RollbackTriggers** *(list) --* 

          The triggers to monitor during stack creation or update actions.

           

          By default, CloudFormation saves the rollback triggers specified for a stack and applies them to any subsequent update operations for the stack, unless you specify otherwise. If you do specify rollback triggers for this parameter, those triggers replace any list of triggers previously specified for the stack. This means:

           

          
          * To use the rollback triggers previously specified for this stack, if any, don't specify this parameter.
           
          * To specify new or updated rollback triggers, you must specify *all* the triggers that you want used for this stack, even triggers you've specified before (for example, when creating the stack or during a previous stack update). Any triggers that you don't include in the updated list of triggers are no longer applied to the stack.
           
          * To remove all currently specified triggers, specify an empty list for this parameter.
          

           

          If a specified trigger is missing, the entire stack operation fails and is rolled back.

          
          

          - *(dict) --* 

            A rollback trigger CloudFormation monitors during creation and updating of stacks. If any of the alarms you specify goes to ALARM state during the stack operation or within the specified monitoring period afterwards, CloudFormation rolls back the entire stack operation.

            
            

            - **Arn** *(string) --* 

              The Amazon Resource Name (ARN) of the rollback trigger.

               

              If a specified trigger is missing, the entire stack operation fails and is rolled back.

              
            

            - **Type** *(string) --* 

              The resource type of the rollback trigger. Specify either `AWS\:\:CloudWatch\:\:Alarm <https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-resource-cloudwatch-alarm.html>`__ or `AWS\:\:CloudWatch\:\:CompositeAlarm <https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-resource-cloudwatch-compositealarm.html>`__ resource types.

              
        
      
        

        - **MonitoringTimeInMinutes** *(integer) --* 

          The amount of time, in minutes, during which CloudFormation should monitor all the rollback triggers after the stack creation or update operation deploys all necessary resources.

           

          The default is 0 minutes.

           

          If you specify a monitoring period but don't specify any rollback triggers, CloudFormation still waits the specified period of time before cleaning up old resources after update operations. You can use this monitoring period to perform any manual stack validation desired, and manually cancel the stack creation or update (using `CancelUpdateStack <https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_CancelUpdateStack.html>`__, for example) as necessary.

           

          If you specify 0 for this parameter, CloudFormation still monitors the specified rollback triggers during stack creation and update operations. Then, for update operations, it begins disposing of old resources immediately once the operation completes.

          
    
      

      - **Capabilities** *(list) --* 

        If you execute the change set, the list of capabilities that were explicitly acknowledged when the change set was created.

        
        

        - *(string) --* 
    
      

      - **Tags** *(list) --* 

        If you execute the change set, the tags that will be associated with the stack.

        
        

        - *(dict) --* 

          The Tag type enables you to specify a key-value pair that can be used to store information about an CloudFormation stack.

          
          

          - **Key** *(string) --* 

            A string used to identify this tag. You can specify a maximum of 128 characters for a tag key. Tags owned by Amazon Web Services have the reserved prefix: ``aws:``.

            
          

          - **Value** *(string) --* 

            A string that contains the value for this tag. You can specify a maximum of 256 characters for a tag value.

            
      
    
      

      - **Changes** *(list) --* 

        A list of ``Change`` structures that describes the resources CloudFormation changes if you execute the change set.

        
        

        - *(dict) --* 

          The ``Change`` structure describes the changes CloudFormation will perform if you execute the change set.

          
          

          - **Type** *(string) --* 

            The type of entity that CloudFormation changes.

             

            
            * ``Resource`` This change is for a resource.
            

            
          

          - **HookInvocationCount** *(integer) --* 

            Is either ``null``, if no Hooks invoke for the resource, or contains the number of Hooks that will invoke for the resource.

            
          

          - **ResourceChange** *(dict) --* 

            A ``ResourceChange`` structure that describes the resource and action that CloudFormation will perform.

            
            

            - **PolicyAction** *(string) --* 

              The action that will be taken on the physical resource when the change set is executed.

               

              
              * ``Delete`` The resource will be deleted.
               
              * ``Retain`` The resource will be retained.
               
              * ``Snapshot`` The resource will have a snapshot taken.
               
              * ``ReplaceAndDelete`` The resource will be replaced and then deleted.
               
              * ``ReplaceAndRetain`` The resource will be replaced and then retained.
               
              * ``ReplaceAndSnapshot`` The resource will be replaced and then have a snapshot taken.
              

              
            

            - **Action** *(string) --* 

              The action that CloudFormation takes on the resource, such as ``Add`` (adds a new resource), ``Modify`` (changes a resource), ``Remove`` (deletes a resource), ``Import`` (imports a resource), ``Dynamic`` (exact action for the resource can't be determined), or ``SyncWithActual`` (resource will not be changed, only CloudFormation metadata will change).

              
            

            - **LogicalResourceId** *(string) --* 

              The resource's logical ID, which is defined in the stack's template.

              
            

            - **PhysicalResourceId** *(string) --* 

              The resource's physical ID (resource name). Resources that you are adding don't have physical IDs because they haven't been created.

              
            

            - **ResourceType** *(string) --* 

              The type of CloudFormation resource, such as ``AWS::S3::Bucket``.

              
            

            - **Replacement** *(string) --* 

              For the ``Modify`` action, indicates whether CloudFormation will replace the resource by creating a new one and deleting the old one. This value depends on the value of the ``RequiresRecreation`` property in the ``ResourceTargetDefinition`` structure. For example, if the ``RequiresRecreation`` field is ``Always`` and the ``Evaluation`` field is ``Static``, ``Replacement`` is ``True``. If the ``RequiresRecreation`` field is ``Always`` and the ``Evaluation`` field is ``Dynamic``, ``Replacement`` is ``Conditional``.

               

              If you have multiple changes with different ``RequiresRecreation`` values, the ``Replacement`` value depends on the change with the most impact. A ``RequiresRecreation`` value of ``Always`` has the most impact, followed by ``Conditional``, and then ``Never``.

              
            

            - **Scope** *(list) --* 

              For the ``Modify`` action, indicates which resource attribute is triggering this update, such as a change in the resource attribute's ``Metadata``, ``Properties``, or ``Tags``.

              
              

              - *(string) --* 
          
            

            - **ResourceDriftStatus** *(string) --* 

              The drift status of the resource. Valid values:

               

              
              * ``IN_SYNC`` – The resource matches its template definition.
               
              * ``MODIFIED`` – Resource properties were modified outside CloudFormation.
               
              * ``DELETED`` – The resource was deleted outside CloudFormation.
               
              * ``NOT_CHECKED`` – CloudFormation doesn’t currently return this value.
               
              * ``UNKNOWN`` – Drift status could not be determined.
               
              * ``UNSUPPORTED`` – Resource type does not support actual state comparison.
              

               

              Only present for drift-aware change sets.

              
            

            - **ResourceDriftIgnoredAttributes** *(list) --* 

              List of resource attributes for which drift was ignored.

              
              

              - *(dict) --* 

                The ``ResourceDriftIgnoredAttribute`` data type.

                
                

                - **Path** *(string) --* 

                  Path of the resource attribute for which drift was ignored.

                  
                

                - **Reason** *(string) --* 

                  Reason why drift was ignored for the attribute, can have 2 possible values:

                   

                  
                  * ``WRITE_ONLY_PROPERTY`` - Property is not included in read response for the resource’s live state.
                   
                  * ``MANAGED_BY_AWS`` - Property is managed by an Amazon Web Services service and is expected to be dynamically modified.
                  

                  
            
          
            

            - **Details** *(list) --* 

              For the ``Modify`` action, a list of ``ResourceChangeDetail`` structures that describes the changes that CloudFormation will make to the resource.

              
              

              - *(dict) --* 

                For a resource with ``Modify`` as the action, the ``ResourceChange`` structure describes the changes CloudFormation will make to that resource.

                
                

                - **Target** *(dict) --* 

                  A ``ResourceTargetDefinition`` structure that describes the field that CloudFormation will change and whether the resource will be recreated.

                  
                  

                  - **Attribute** *(string) --* 

                    Indicates which resource attribute is triggering this update, such as a change in the resource attribute's ``Metadata``, ``Properties``, or ``Tags``.

                    
                  

                  - **Name** *(string) --* 

                    If the ``Attribute`` value is ``Properties``, the name of the property. For all other attributes, the value is null.

                    
                  

                  - **RequiresRecreation** *(string) --* 

                    If the ``Attribute`` value is ``Properties``, indicates whether a change to this property causes the resource to be recreated. The value can be ``Never``, ``Always``, or ``Conditionally``. To determine the conditions for a ``Conditionally`` recreation, see the update behavior for that property in the `Amazon Web Services resource and property types reference <https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-template-resource-type-ref.html>`__ in the *CloudFormation User Guide*.

                    
                  

                  - **Path** *(string) --* 

                    The property path of the property.

                    
                  

                  - **BeforeValue** *(string) --* 

                    The value of the property before the change is executed. Large values can be truncated.

                    
                  

                  - **AfterValue** *(string) --* 

                    The value of the property after the change is executed. Large values can be truncated.

                    
                  

                  - **BeforeValueFrom** *(string) --* 

                    Indicates the source of the before value. Valid values:

                     

                    
                    * ``ACTUAL_STATE`` – The before value represents current actual state.
                     
                    * ``PREVIOUS_DEPLOYMENT_STATE`` – The before value represents the previous CloudFormation deployment state.
                    

                     

                    Only present for drift-aware change sets.

                    
                  

                  - **AfterValueFrom** *(string) --* 

                    Indicates the source of the after value. Valid value:

                     

                    
                    * ``TEMPLATE`` – The after value comes from the new template.
                    

                     

                    Only present for drift-aware change sets.

                    
                  

                  - **Drift** *(dict) --* 

                    Detailed drift information for the resource property, including actual values, previous deployment values, and drift detection timestamps.

                    
                    

                    - **PreviousValue** *(string) --* 

                      The configuration value from the previous CloudFormation deployment.

                      
                    

                    - **ActualValue** *(string) --* 

                      The current live configuration value of the resource property.

                      
                    

                    - **DriftDetectionTimestamp** *(datetime) --* 

                      The timestamp when drift was detected for this resource property.

                      
                
                  

                  - **AttributeChangeType** *(string) --* 

                    The type of change to be made to the property if the change is executed.

                     

                    
                    * ``Add`` The item will be added.
                     
                    * ``Remove`` The item will be removed.
                     
                    * ``Modify`` The item will be modified.
                     
                    * ``SyncWithActual`` The drift status of this item will be reset but the item will not be modified.
                    

                    
              
                

                - **Evaluation** *(string) --* 

                  Indicates whether CloudFormation can determine the target value, and whether the target value will change before you execute a change set.

                   

                  For ``Static`` evaluations, CloudFormation can determine that the target value will change, and its value. For example, if you directly modify the ``InstanceType`` property of an EC2 instance, CloudFormation knows that this property value will change, and its value, so this is a ``Static`` evaluation.

                   

                  For ``Dynamic`` evaluations, can't determine the target value because it depends on the result of an intrinsic function, such as a ``Ref`` or ``Fn::GetAtt`` intrinsic function, when the stack is updated. For example, if your template includes a reference to a resource that's conditionally recreated, the value of the reference (the physical ID of the resource) might change, depending on if the resource is recreated. If the resource is recreated, it will have a new physical ID, so all references to that resource will also be updated.

                  
                

                - **ChangeSource** *(string) --* 

                  The group to which the ``CausingEntity`` value belongs. There are five entity groups:

                   

                  
                  * ``ResourceReference`` entities are ``Ref`` intrinsic functions that refer to resources in the template, such as ``{ "Ref" : "MyEC2InstanceResource" }``.
                   
                  * ``ParameterReference`` entities are ``Ref`` intrinsic functions that get template parameter values, such as ``{ "Ref" : "MyPasswordParameter" }``.
                   
                  * ``ResourceAttribute`` entities are ``Fn::GetAtt`` intrinsic functions that get resource attribute values, such as ``{ "Fn::GetAtt" : [ "MyEC2InstanceResource", "PublicDnsName" ] }``.
                   
                  * ``DirectModification`` entities are changes that are made directly to the template.
                   
                  * ``Automatic`` entities are ``AWS::CloudFormation::Stack`` resource types, which are also known as nested stacks. If you made no changes to the ``AWS::CloudFormation::Stack`` resource, CloudFormation sets the ``ChangeSource`` to ``Automatic`` because the nested stack's template might have changed. Changes to a nested stack's template aren't visible to CloudFormation until you run an update on the parent stack.
                   
                  * ``NoModification`` entities are changes made to the template that matches the actual state of the resource.
                  

                  
                

                - **CausingEntity** *(string) --* 

                  The identity of the entity that triggered this change. This entity is a member of the group that's specified by the ``ChangeSource`` field. For example, if you modified the value of the ``KeyPairName`` parameter, the ``CausingEntity`` is the name of the parameter ( ``KeyPairName``).

                   

                  If the ``ChangeSource`` value is ``DirectModification``, no value is given for ``CausingEntity``.

                  
            
          
            

            - **ChangeSetId** *(string) --* 

              The change set ID of the nested change set.

              
            

            - **ModuleInfo** *(dict) --* 

              Contains information about the module from which the resource was created, if the resource was created from a module included in the stack template.

              
              

              - **TypeHierarchy** *(string) --* 

                A concatenated list of the module type or types that contains the resource. Module types are listed starting with the inner-most nested module, and separated by ``/``.

                 

                In the following example, the resource was created from a module of type ``AWS::First::Example::MODULE``, that's nested inside a parent module of type ``AWS::Second::Example::MODULE``.

                 

                ``AWS::First::Example::MODULE/AWS::Second::Example::MODULE``

                
              

              - **LogicalIdHierarchy** *(string) --* 

                A concatenated list of the logical IDs of the module or modules that contains the resource. Modules are listed starting with the inner-most nested module, and separated by ``/``.

                 

                In the following example, the resource was created from a module, ``moduleA``, that's nested inside a parent module, ``moduleB``.

                 

                ``moduleA/moduleB``

                 

                For more information, see `Reference module resources in CloudFormation templates <https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/module-ref-resources.html>`__ in the *CloudFormation User Guide*.

                
          
            

            - **BeforeContext** *(string) --* 

              An encoded JSON string that contains the context of the resource before the change is executed.

              
            

            - **AfterContext** *(string) --* 

              An encoded JSON string that contains the context of the resource after the change is executed.

              
            

            - **PreviousDeploymentContext** *(string) --* 

              Information about the resource's state from the previous CloudFormation deployment.

              
        
      
    
      

      - **NextToken** *(string) --* 

        If the output exceeds 1 MB, a string that identifies the next page of changes. If there is no additional page, this value is null.

        
      

      - **IncludeNestedStacks** *(boolean) --* 

        Verifies if ``IncludeNestedStacks`` is set to ``True``.

        
      

      - **ParentChangeSetId** *(string) --* 

        Specifies the change set ID of the parent change set in the current nested change set hierarchy.

        
      

      - **RootChangeSetId** *(string) --* 

        Specifies the change set ID of the root change set in the current nested change set hierarchy.

        
      

      - **OnStackFailure** *(string) --* 

        Determines what action will be taken if stack creation fails. When this parameter is specified, the ``DisableRollback`` parameter to the `ExecuteChangeSet <https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_ExecuteChangeSet.html>`__ API operation must not be specified. This must be one of these values:

         

        
        * ``DELETE`` - Deletes the change set if the stack creation fails. This is only valid when the ``ChangeSetType`` parameter is set to ``CREATE``. If the deletion of the stack fails, the status of the stack is ``DELETE_FAILED``.
         
        * ``DO_NOTHING`` - if the stack creation fails, do nothing. This is equivalent to specifying ``true`` for the ``DisableRollback`` parameter to the `ExecuteChangeSet <https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_ExecuteChangeSet.html>`__ API operation.
         
        * ``ROLLBACK`` - if the stack creation fails, roll back the stack. This is equivalent to specifying ``false`` for the ``DisableRollback`` parameter to the `ExecuteChangeSet <https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_ExecuteChangeSet.html>`__ API operation.
        

        
      

      - **ImportExistingResources** *(boolean) --* 

        Indicates if the change set imports resources that already exist.

         

        .. note::

          

          This parameter can only import resources that have `custom names <https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-properties-name.html>`__ in templates. To import resources that do not accept custom names, such as EC2 instances, use the `resource import <https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/resource-import.html>`__ feature instead.

          

        
      

      - **DeploymentMode** *(string) --* 

        The deployment mode specified when the change set was created. Valid value is ``REVERT_DRIFT``. Only present for drift-aware change sets.

        
  
  **Exceptions**
  
  *   :py:class:`CloudFormation.Client.exceptions.ChangeSetNotFoundException`

  