Multi-region data sovereignty deployment - Routing Alternatives

For such a multi-region data sovereignty requirement, you need a solution that routes your customers to the correct regional endpoint based on their designated region without exposing customer lists through DNS lookups. Here are some approaches that align with AWS best practices:

1. Route 53 Geoproximity Routing with Traffic Policies:

   • Use Route 53’s geoproximity routing to direct traffic based on the geographic location of your users.
   • Implement traffic policies to handle complex routing requirements.
   • This method does not expose any customer lists, as the routing is based on the location of the DNS queries, not a list of customers.
   • However, this doesn’t meet the requirement for users to stick to their initial region after signup, as the routing is dynamic.

2. AWS Global Accelerator:

   • Global Accelerator provides static IP addresses that act as a fixed entry point to your applications hosted in multiple AWS Regions.
   • It uses the AWS global network to optimize the path to your application, which can improve performance.
   • You can use application-level logic to route the customer to the appropriate regional endpoint based on their signup information.
   • This way, you won’t expose any DNS listings, and the application logic remains hidden.

3. Lambda@Edge for Custom Routing:

   • Using Lambda@Edge allows you to run your code in AWS locations globally without provisioning or managing servers, allowing you to execute functions that customize the content that CloudFront delivers.
   • You can securely store your EU/USA customer designation in an encrypted S3 bucket or AWS Systems Manager Parameter Store, and your Lambda@Edge function can query this storage to determine the correct routing.
   • This approach ensures that customer data is not exposed through DNS and enables dynamic resolution without a static list in the function.

4. CloudFront Functions for Lightweight Routing:

   • CloudFront Functions run closer to the user, at CloudFront edge locations, and are suitable for simple header manipulations, URL rewrites/redirects, and other lightweight processing.
   • You could use a CloudFront function to inspect the incoming requests and rewrite the URL to point to the correct regional domain based on a static mapping within the function.
   • While you can use a static list within CloudFront Functions, this might not be scalable or easy to manage if the list changes frequently.

5. Client-Side Routing:

   • Implement client-side logic in your application to direct users to the correct regional endpoint after login. This way, the initial DNS query goes to a generic endpoint, and subsequent requests are routed based on the logic in the application.
   • This requires secure handling of the client logic and ensuring it aligns with data sovereignty and privacy regulations.

Each of these methods has its trade-offs regarding management overhead, cost, performance, and complexity. For instance, Lambda@Edge provides more flexibility and can handle dynamic lists, but it introduces extra latency compared to a straightforward DNS routing approach. CloudFront Functions are more limited in capability but offer lower latency.

When implementing any of these solutions, ensure that you are encrypting sensitive data at rest and in transit, and that you are following the principle of least privilege when granting access to AWS resources.

To maintain compliance with data sovereignty requirements, you should also ensure that no personal data is transferred between regions unless it is encrypted and the transfer is compliant with local regulations (like GDPR in the EU). Consider consulting with a legal expert to ensure that your solution complies with all relevant data protection laws.

For detailed implementation guides and the latest best practices, consult the AWS documentation for Route 53, Global Accelerator, Lambda@Edge, and CloudFront Functions.