Change sets for nested stacks

With change sets for nested stacks you can preview the changes to your application and infrastructure resources across the entire nested stack hierarchy and proceed with updates when you've confirmed that all the changes are as intended.

See the following sections for more details about change sets for nested stacks:

Overview of change sets and nested stacks

Change sets for nested stacks combines the following features together to expand the scope of previewing changes to the entire stack hierarchy:

• Change sets is a CloudFormation capability that offers a preview of how proposed changes to a stack will impact existing or newly created resources. Upon creating a change set, CloudFormation provides a list of proposed changes by comparing your stack with the changes to the resources you submitted. For more information about change sets, see Update CloudFormation stacks using change sets.

• Nested stacks are stacks created as part of other stacks. For example, you might have networking and security related resources in one nested stack and application resources in another. Partitioning application models this way helps with code maintainability and reuse. For more information about nested stacks, see Embed stacks within other stacks using nested stacks.

Working with change sets for nested stacks (console)

• Create a change set – Creates a change set by submitting changes from any level of the stack hierarchy. You can submit a modified stack template or modified input parameter values and CloudFormation compares your nested stack with the changes that you submitted to generate a change set. Change sets for nested stacks is enabled by default in the CloudFormation console. For more information, see Create a change set.

  

  Note

  A root change set is the change set associated with the stack from which the whole hierarchy of change sets are created. You must execute or delete change sets for nested stacks from the root change set.

• View the change set – Visualize changes to resources inside nested stacks before executing them. You can view the proposed changes in the Changes section of your change set by navigating through the current stack and its nested change sets. For more information, see View a change set.

• Execute the change set – Execute the changes described in the change set that pertain to the current stack and its descendants. The execute operation must be made from the root change set. For more information, see Execute a change set.

• Delete the change set – Removes the change sets from the current stack. Deleting a change set helps to prevent you or another user from accidentally initiating a change set that shouldn't be applied. The delete operation must be executed from the root change set. For more information, see Delete a change set.

Working with change sets for nested stacks (AWS CLI)

create-change-set

• create-change-set – Change sets for nested stacks isn't enabled by default for the AWS CLI. To create a change set for the entire stack hierarchy, specify the --include-nested-stacks option. For more information, see Create a change set.

The following AWS CLI example creates a change set for the specified root stack.

aws cloudformation create-change-set \
    --stack-name my-root-stack \
    --change-set-name my-root-stack-change-set \
    --template-body file://template.yaml \
    --capabilities CAPABILITY_IAM \
    --include-nested-stacks

The following is example output.

{
    "Id":"arn:aws:cloudformation:us-west-2:123456789012:changeSet/my-root-stack-change-set/4eca1a01-e285-xmpl-8026-9a1967bfb4b0",
    "StackId": "arn:aws:cloudformation:us-west-2:123456789012:Stack/my-root-stack/d0a825a0-e4cd-xmpl-b9fb-061c69e99204"
}

describe-change-set

• describe-change-set – Returns a list of changes that CloudFormation will make if you execute the change set. If the change set specified contains child change sets that belong to nested stacks, then ChangeSetId will return information about that change set. For more information, see View a change set.

The following AWS CLI example describes the change set for the specified root stack.

aws cloudformation describe-change-set \
    --change-set-name my-root-stack-change-set \
    --stack-name my-root-stack

The following is example output.

{
    "Changes": [
        {
            "Type": "Resource",
            "ResourceChange": {
                "Action": "Modify",
                "LogicalResourceId": "ChildStack",
                "PhysicalResourceId": "arn:aws:cloudformation:us-west-2:123456789012:stack/my-nested-stack/d0a825a0-e4cd-xmpl-b9fb-061c69e99205",
                "ResourceType": "AWS::CloudFormation::Stack",
                "Replacement": "False",
                "ChangeSetId": "arn:aws:cloudformation:us-west-2:123456789012:changeSet/my-nested-stack-change-set/4eca1a01-e285-xmpl-8026-9a1967bfb4b0",
                "Scope": [
                    "Properties"
                ],
                "Details": [
                    {
                        "Target": {
                            "Attribute": "Properties",
                            "RequiresRecreation": "Never"
                        },
                        "Evaluation": "Dynamic",
                        "ChangeSource": "Automatic"
                    }
                ]
            }
        }
    ],
    "ChangeSetName": "my-root-stack-change-set",
    "ChangeSetId": "arn:aws:cloudformation:us-west-2:123456789012:changeSet/my-root-stack-change-set/4eca1a01-e285-xmpl-8026-9a1967bfb4b0",
    "StackId": "arn:aws:cloudformation:us-west-2:123456789012:stack/my-root-stack/d0a825a0-e4cd-xmpl-b9fb-061c69e99204",
    "StackName": "my-root-stack",
    "IncludeNestedStacks": true,
    "ParentChangeSetId": null,
    "RootChangeSetId": null,
    "Description": null,
    "Parameters": null,
    "CreationTime": "2020-11-18T05:20:56.651Z",
    "ExecutionStatus": "AVAILABLE",
    "Status": "CREATE_COMPLETE",
    "StatusReason": null,
    "NotificationARNs": [
        
    ],
    "RollbackConfiguration": {
        
    },
    "Capabilities": [
        "CAPABILITY_IAM"
    ],
    "Tags": null
}

The following AWS CLI example describes the change set for the specified nested stack.

aws cloudformation describe-change-set \
    --change-set-name my-nested-stack-change-set \
    --stack-name my-nested-stack

The following is example output.

{
    "Changes": [
        {
            "Type": "Resource",
            "ResourceChange": {
                "Action": "Modify",
                "LogicalResourceId": "function",
                "PhysicalResourceId": "my-function",
                "ResourceType": "AWS::Lambda::Function",
                "Replacement": "False",
                "ChangeSetId": null,
                "Scope": [
                    "Properties"
                ],
                "Details": [
                    {
                        "Target": {
                            "Attribute": "Properties",
                            "Name": "Timeout",
                            "RequiresRecreation": "Never"
                        },
                        "Evaluation": "Static",
                        "ChangeSource": "DirectModification"
                    }
                ]
            }
        }
    ],
    "ChangeSetName": "my-nested-stack-change-set",
    "ChangeSetId": "arn:aws:cloudformation:us-west-2:123456789012:changeSet/my-nested-stack-change-set/4eca1a01-e285-xmpl-8026-9a1967bfb4b0",
    "StackId": "arn:aws:cloudformation:us-west-2:123456789012:stack/my-nested-stack/d0a825a0-e4cd-xmpl-b9fb-061c69e99205",
    "ParentChangeSetId": "arn:aws:cloudformation:us-west-2:123456789012:changeSet/my-root-stack-change-set/4eca1a01-e285-xmpl-8026-9a1967bfb4b0",
    "RootChangeSetId": "arn:aws:cloudformation:us-west-2:123456789012:changeSet/my-root-stack-change-set/4eca1a01-e285-xmpl-8026-9a1967bfb4b0",
    "IncludeNestedStacks": true,
    "StackName": "my-nested-stack",
    "Description": null,
    "Parameters": null,
    "CreationTime": "2020-11-18T05:20:56.651Z",
    "ExecutionStatus": "UNAVAILABLE",
    "Status": "CREATE_COMPLETE",
    "StatusReason": "Executable from root change set",
    "NotificationARNs": [
        
    ],
    "RollbackConfiguration": {
        
    },
    "Capabilities": [
        "CAPABILITY_IAM"
    ],
    "Tags": null
}

execute-change-set

• execute-change-set – Creates or updates a stack using the input information that was provided when the specified change set was created. To create a change set for the entire stack hierarchy, you must specify the –-include-nested-stacks option during the create-change-set operation. For more information, see Execute a change set.

  Note

  execute-change-set must be executed from the root change set and will apply the change set on the whole hierarchy of stacks.

The following AWS CLI example executes a change set for the specified root stack.

aws cloudformation execute-change-set \
    --stack-name my-root-stack \
    --change-set-name my-root-stack-change-set

delete-change-set

• delete-change-set – Deletes the specified change set. Deleting change sets ensures that no one uses the wrong change set. Deleting change sets is asynchronous for change sets created with the –-include-nested-stacks option. For more information, see Delete a change set.

  Note

  delete-change-set must be executed from the root change set and will delete the whole hierarchy of change sets. Nested stacks in the REVIEW_IN_PROGRESS status will also be deleted if they were created during the create-change-set operation.

The following AWS CLI example deletes the change set for the specified root stack.

aws cloudformation delete-change-set \
    --stack-name my-root-stack \ 
    --change-set-name my-root-stack-change-set