cdk-stacksets

CDK StackSets Construct Library

---

The APIs of higher level constructs in this module are experimental and under active development. They are subject to non-backward compatible changes or removal in any future version. These are not subject to the Semantic Versioning model and breaking changes will be announced in the release notes. This means that while you may use them, you may need to update your source code when upgrading to a newer version of this package.

---

This construct library allows you to define AWS CloudFormation StackSets.

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet")

StackSet(stack, "StackSet",
    target=StackSetTarget.from_accounts(
        regions=["us-east-1"],
        accounts=["11111111111"],
        parameter_overrides={
            "SomeParam": "overrideValue"
        }
    ),
    template=StackSetTemplate.from_stack_set_stack(stack_set_stack)
)

Installing

TypeScript/JavaScript

npm install cdk-stacksets

Python

pip install cdk-stacksets

Java

// add this to your pom.xml
<dependency>
    <groupId>io.github.cdklabs</groupId>
    <artifactId>cdk-stacksets</artifactId>
    <version>0.0.0</version> // replace with version
</dependency>

.NET

dotnet add package CdklabsCdkStacksets --version X.X.X

Go

go get cdk-stacksets-go

Creating a StackSet Stack

StackSets allow you to deploy a single CloudFormation template across multiple AWS accounts and regions. Typically when creating a CDK Stack that will be deployed across multiple environments, the CDK will synthesize separate Stack templates for each environment (account/region combination). Because of the way that StackSets work, StackSet Stacks behave differently. For Stacks that will be deployed via StackSets a single Stack is defined and synthesized. Any environmental differences must be encoded using Parameters.

A special class was created to handle the uniqueness of the StackSet Stack. You declare a StackSetStack the same way that you declare a normal Stack, but there are a couple of differences. StackSetStacks have a couple of special requirements/limitations when compared to Stacks.

Requirements

• Must be created in the scope of a Stack
• Must be environment agnostic

Limitations

• Does not support Docker container assets

Once you create a StackSetStack you can create resources within the stack.

stack = Stack()
stack_set_stack = StackSetStack(stack, "StackSet")

iam.Role(stack_set_stack, "MyRole",
    assumed_by=iam.ServicePrincipal("myservice.amazonaws.com")
)

Or

class MyStackSet(StackSetStack):
    def __init__(self, scope, id):
        super().__init__(scope, id)

        iam.Role(self, "MyRole",
            assumed_by=iam.ServicePrincipal("myservice.amazonaws.com")
        )

Creating a StackSet

AWS CloudFormation StackSets enable you to create, update, or delete stacks across multiple accounts and AWS Regions with a single operation. Using an administrator account, you define and manage an AWS CloudFormation template, and use the template as the basis for provisioning stacks into selected target accounts across specific AWS Regions.

There are two methods for defining where the StackSet should be deployed. You can either define individual accounts, or you can define AWS Organizations organizational units.

Deploying to individual accounts

Deploying to individual accounts requires you to specify the account ids. If you want to later deploy to additional accounts, or remove the stackset from accounts, this has to be done by adding/removing the account id from the list.

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet")

StackSet(stack, "StackSet",
    target=StackSetTarget.from_accounts(
        regions=["us-east-1"],
        accounts=["11111111111"]
    ),
    template=StackSetTemplate.from_stack_set_stack(stack_set_stack)
)

Deploying to organizational units

AWS Organizations is an AWS service that enables you to centrally manage and govern multiple accounts. AWS Organizations allows you to define organizational units (OUs) which are logical groupings of AWS accounts. OUs enable you to organize your accounts into a hierarchy and make it easier for you to apply management controls. For a deep dive on OU best practices you can read the Best Practices for Organizational Units with AWS Organizations blog post.

You can either specify the organization itself, or individual OUs. By default the StackSet will be deployed to all AWS accounts that are part of the OU. If the OU is nested it will also deploy to all accounts that are part of any nested OUs.

For example, given the following org hierarchy

graph TD
  root-->ou-1;
  root-->ou-2;
  ou-1-->ou-3;
  ou-1-->ou-4;
  ou-3-->account-1;
  ou-3-->account-2;
  ou-4-->account-4;
  ou-2-->account-3;
  ou-2-->account-5;

You could deploy to all AWS accounts under OUs ou-1, ou-3, ou-4 by specifying the following:

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet")

StackSet(stack, "StackSet",
    target=StackSetTarget.from_organizational_units(
        regions=["us-east-1"],
        organizational_units=["ou-1"]
    ),
    template=StackSetTemplate.from_stack_set_stack(stack_set_stack)
)

This would deploy the StackSet to account-1, account-2, account-4.

If there are specific AWS accounts that are part of the specified OU hierarchy that you would like to exclude, this can be done by specifying excludeAccounts.

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet")

StackSet(stack, "StackSet",
    target=StackSetTarget.from_organizational_units(
        regions=["us-east-1"],
        organizational_units=["ou-1"],
        exclude_accounts=["account-2"]
    ),
    template=StackSetTemplate.from_stack_set_stack(stack_set_stack)
)

This would deploy only to account-1 & account-4, and would exclude account-2.

Sometimes you might have individual accounts that you would like to deploy the StackSet to, but you do not want to include the entire OU. To do that you can specify additionalAccounts.

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet")

StackSet(stack, "StackSet",
    target=StackSetTarget.from_organizational_units(
        regions=["us-east-1"],
        organizational_units=["ou-1"],
        additional_accounts=["account-5"]
    ),
    template=StackSetTemplate.from_stack_set_stack(stack_set_stack)
)

This would deploy the StackSet to account-1, account-2, account-4 & account-5.

StackSet permissions

There are two modes for managing StackSet permissions (i.e. where StackSets can deploy & what resources they can create). A StackSet can either be Service Managed or Self Managed.

You can control this through the deploymentType parameter.

Service Managed

When a StackSet is service managed, the permissions are managed by AWS Organizations. This allows the StackSet to deploy the Stack to any account within the organization. In addition, the StackSet will be able to create any type of resource.

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet")

StackSet(stack, "StackSet",
    target=StackSetTarget.from_organizational_units(
        regions=["us-east-1"],
        organizational_units=["ou-1"]
    ),
    deployment_type=DeploymentType.service_managed(),
    template=StackSetTemplate.from_stack_set_stack(stack_set_stack)
)

When you specify serviceManaged deployment type, automatic deployments are enabled by default. Automatic deployments allow the StackSet to be automatically deployed to or deleted from AWS accounts when they are added or removed from the specified organizational units.

Using File Assets

You can use the StackSet's parent stack to facilitate file assets. Behind the scenes, this is accomplished using the BucketDeployment construct from the aws_s3_deployment module. You need to provide a list of buckets outside the scope of the CDK managed asset buckets and ensure you have permissions for the target accounts to pull the artifacts from the supplied bucket(s).

As a basic example, if using a serviceManaged deployment, you just need to give read access to the Organization. You can create the asset bucket in the parent stack, or another stack in the same app and pass the object as a prop. Or, import an existing bucket as needed.

If creating in the parent or sibling stack you could create and export similar to this:

bucket = s3.Bucket(self, "Assets",
    bucket_name="prefix-us-east-1"
)

bucket.add_to_resource_policy(
    iam.PolicyStatement(
        actions=["s3:Get*", "s3:List*"],
        resources=[bucket.arn_for_objects("*"), bucket.bucket_arn],
        principals=[iam.OrganizationPrincipal("o-xyz")]
    ))

Then pass as a prop to the StackSet stack:

# bucket: s3.Bucket

stack = Stack()
stack_set_stack = StackSetStack(stack, "MyStackSet",
    asset_buckets=[bucket],
    asset_bucket_prefix="prefix"
)

To faciliate multi region deployments, there is an assetBucketPrefix property. This gets added to the region the Stack Set is deployed to. The stack synthesis for the Stack Set would look for a bucket named prefix-{Region} in the example above. {Region} is whatever region you are deploying the Stack Set to as defined in your target property of the StackSet. You will need to ensure the bucket name is correct based on what was previously created and then passed in.

You can use self-managed StackSet deployments with file assets too but will need to ensure all target accounts roles will have access to the central asset bucket you pass as the property.

Deploying StackSets using CDK Pipelines

You can also deploy StackSets using CDK Pipelines

Below is an example of a Pipeline that deploys from a central account. It also defines separate stages for each "environment" so that you can first test out the stackset in pre-prod environments.

This would be an automated way of deploying the bootstrap stack described in this blog post.

# app: App


class BootstrapStage(Stage):
    def __init__(self, scope, id, *, initialBootstrapTarget, stacksetName=None, env=None, outdir=None, stageName=None, permissionsBoundary=None, policyValidationBeta1=None):
        super().__init__(scope, id, initialBootstrapTarget=initialBootstrapTarget, stacksetName=stacksetName, env=env, outdir=outdir, stageName=stageName, permissionsBoundary=permissionsBoundary, policyValidationBeta1=policyValidationBeta1)

        stack = Stack(self, "BootstrapStackSet")

        bootstrap = Bootstrap(stack, "CDKToolkit")

        stack_set = StackSet(stack, "StackSet",
            template=StackSetTemplate.from_stack_set_stack(bootstrap),
            target=initial_bootstrap_target,
            capabilities=[Capability.NAMED_IAM],
            managed_execution=True,
            stack_set_name=stackset_name,
            deployment_type=DeploymentType.service_managed(
                delegated_admin=True,
                auto_deploy_enabled=True,
                auto_deploy_retain_stacks=False
            ),
            operation_preferences=OperationPreferences(
                region_concurrency_type=RegionConcurrencyType.PARALLEL,
                max_concurrent_percentage=100,
                failure_tolerance_percentage=99
            )
        )

pipeline = pipelines.CodePipeline(self, "BootstrapPipeline",
    synth=pipelines.ShellStep("Synth",
        commands=["yarn install --frozen-lockfile", "npx cdk synth"
        ],
        input=pipelines.CodePipelineSource.connection("myorg/myrepo", "main",
            connection_arn="arn:aws:codestar-connections:us-east-2:111111111111:connection/ca65d487-ca6e-41cc-aab2-645db37fdb2b"
        )
    ),
    self_mutation=True
)

regions = ["us-east-1", "us-east-2", "us-west-2", "eu-west-2", "eu-west-1", "ap-south-1", "ap-southeast-1"
]

pipeline.add_stage(
    BootstrapStage(app, "DevBootstrap",
        env=Environment(
            region="us-east-1",
            account="111111111111"
        ),
        stackset_name="CDKToolkit-dev",
        initial_bootstrap_target=StackSetTarget.from_organizational_units(
            regions=regions,
            organizational_units=["ou-hrza-ar333427"]
        )
    ))

pipeline.add_stage(
    BootstrapStage(app, "ProdBootstrap",
        env=Environment(
            region="us-east-1",
            account="111111111111"
        ),
        stackset_name="CDKToolkit-prd",
        initial_bootstrap_target=StackSetTarget.from_organizational_units(
            regions=regions,
            organizational_units=["ou-hrza-bb999427", "ou-hraa-ar111127"]
        )
    ))