Simplifying Cross-Account and Cross-Region Infrastructure References with AWS CloudFormation and CDK

Why this matters

Infrastructure as code (IaC) is a cornerstone for managing cloud resources predictably and repeatably, especially when operating at scale. In AWS environments, CloudFormation stacks represent modular units of infrastructure resources. As businesses grow and distribute workloads across multiple accounts and regions—common for compliance, fault tolerance, or organizational needs—teams frequently need to connect stacks in one account or region to outputs generated in another. This could include connecting a database endpoint in one region with an application in another or sharing network resources across accounts.

Historically, this cross-account and cross-region referencing has been cumbersome. It often requires manual export/import steps, custom scripts, or reliance on intermediate services, which introduces operational overhead and potential for errors. For founders and CTOs juggling cloud spend and compliance demands, every additional manual step can lead to delayed deployments or misconfigured environments.

A more straightforward method to reference outputs across boundaries reduces friction. It promotes cleaner architecture, easier troubleshooting, and more maintainable codebases. The recent addition of the Fn::GetStackOutput intrinsic function in AWS CloudFormation and its integration with the AWS CDK is a meaningful improvement toward this goal.

What usually goes wrong

Without a native, integrated way to reference stack outputs across accounts or regions, teams often resort to brittle workarounds. One common approach involves exporting outputs in one stack and manually importing them in another, which can lead to synchronization issues. If an output changes but the import isn’t updated promptly, stacks drift out of alignment, leading to deployment failures or runtime errors.

Alternatively, some teams rely on custom automation scripts or external state management tools to propagate output values. These solutions add complexity and maintenance burdens. They often lack visibility in CloudFormation drift detection or CloudTrail, making auditing and compliance verification challenging. In healthcare or professional services, where HIPAA and SOC 2 compliance require tight controls and traceability, these risks are significant.

Cross-region referencing further complicates matters because CloudFormation traditionally does not support direct references to stacks in different regions. This limitation forces duplication of resources or reliance on asynchronous communication methods, which increases latency and operational overhead. The result is slower infrastructure deployments and increased cloud spend from redundant resources.

The lack of a unified solution also burdens engineering teams with fragmented codebases and inconsistent infrastructure definitions. This fragmentation slows iteration and increases the risk of mistakes during rollouts, which can impact service availability and distract leadership from core business priorities.

A better Cloudain-style approach

The introduction of the Fn::GetStackOutput function represents a practical step forward. This intrinsic function enables direct referencing of outputs from stacks deployed in different accounts and regions within CloudFormation templates and CDK applications. It simplifies the infrastructure code by removing the need for export/import constructs or external synchronization mechanisms.

By embedding cross-account and cross-region output references declaratively, teams can keep infrastructure definitions more modular and maintainable. This approach aligns well with a platform engineering mindset focused on reducing cognitive overhead and operational toil. It also improves consistency, as stack outputs become first-class references tracked and managed by CloudFormation itself.

From a compliance perspective, relying on native CloudFormation constructs means that output references benefit from the platform’s existing audit trails and drift detection capabilities. This traceability is crucial for healthcare and professional services companies that must demonstrate adherence to regulatory standards.

Moreover, integrating this function through the AWS CDK allows developers to use familiar programming languages and patterns when defining infrastructure. This consolidation reduces context switching and accelerates delivery cycles. The CDK’s abstraction enables richer validations and type checking around output dependencies, further reducing errors.

This method also supports cleaner infrastructure modularity. For example, a shared networking stack in one AWS account can expose outputs consumed by application stacks in other regions or accounts without duplicating resources or writing complex glue code. This approach helps control cloud spend by minimizing redundant provisioning and improving resource lifecycle management.

A simple next step

For teams currently managing cross-account and cross-region references through manual exports or external scripts, evaluating the adoption of Fn::GetStackOutput should be a priority. Starting with a small, non-critical stack interaction is advisable to observe the operational impact and validate integration with existing CI/CD pipelines.

Review existing CloudFormation templates or CDK app code to identify places where outputs are exported and imported manually or where external automation handles state propagation. These are prime candidates for refactoring using the new intrinsic function.

In parallel, revisit IAM permissions and trust relationships between AWS accounts involved in cross-account referencing. Correct permissions are essential to allow CloudFormation stacks to securely access outputs without opening unnecessary access or complicating security posture.

It is also worthwhile to update deployment pipelines to support this pattern, ensuring that stacks are deployed in the correct sequence and dependencies are properly managed. Leveraging the CDK’s context and dependency management features can help orchestrate this smoothly.

Documenting these changes and the rationale behind them aids compliance documentation and onboarding of new engineers. Clear explanations about how outputs are referenced across accounts and regions help reduce future operational friction.

How Cloudain can help

Cloudain’s expertise in designing and implementing scalable AWS infrastructure can assist companies in adopting the Fn::GetStackOutput function to simplify cross-account and cross-region references. By focusing on practical, maintainable infrastructure code and secure cross-boundary access, Cloudain helps engineering teams reduce deployment risk and cloud spend.

With a deep understanding of healthcare and professional services compliance requirements, Cloudain can guide firms through the necessary IAM configuration and operational best practices to maintain governance while smoothing infrastructure workflows. This support ensures organizations can safely evolve their platform engineering practices in line with their business growth.

Engaging Cloudain to review existing CloudFormation and CDK implementations can uncover hidden complexities in output management and propose streamlined, compliant solutions that save time and reduce complexity across AWS environments.