Interoperability and portability are critical considerations when designing and building cloud systems. Having clear policies and procedures in place ensures applications can communicate effectively, data can be seamlessly exchanged, and workloads can be moved between environments as needed. Documenting, communicating, and regularly reviewing these guidelines keeps everyone on the same page.

Where did this come from?

This control comes from the CSA Cloud Controls Matrix v4.0.10 - 2023-09-26. You can download the full matrix here. The CCM provides a comprehensive set of cloud security controls mapped to various standards and regulations. For more background on interoperability and portability in AWS specifically, check out the AWS Cloud Adoption Framework.

Who should care?

This is relevant for:

• Solutions Architects designing multi-cloud or hybrid architectures
• Developers building portable applications
• Engineering leaders wanting flexibility to avoid vendor lock-in
• Compliance officers ensuring adherence to data portability requirements

What is the risk?

Without proper interop and portability:

• Applications may not be able to communicate, leading to silos
• Migrating workloads between clouds or on-prem could be difficult and costly
• Vendor lock-in could limit future options and negotiating power
• Compliance requirements around data portability may not be met

While unlikely to directly cause a breach, lack of interop and portability can significantly hamper an organization's agility and incur major technical debt over time.

What's the care factor?

For companies with a multi-cloud or hybrid strategy, this should be a high priority. It directly impacts the feasibility of their architecture. Smaller shops standardized on a single cloud provider may rate this a lower priority. However, even they would be wise to avoid painting themselves into a corner. Priorities can change.

When is it relevant?

Interop and portability policies should be defined early when:

• Adopting microservices or SOA
• Pursuing a multi-cloud strategy
• Migrating workloads to the cloud
• Needing to meet data portability compliance requirements

It's less of a concern for:

• Monolithic legacy apps running on-prem
• Greenfield apps built cloud-native on a single provider
• Situations where high coupling is desirable for performance/security

What are the trade-offs?

Increasing interoperability and portability isn't free:

• Using generic, lowest-common-denominator services sacrifices cloud-specific optimizations
• Porting apps between clouds requires more abstraction layers
• Testing cross-cloud compatibility adds development overhead
• Maintaining provider-agnostic deployment pipelines is complex

There's a balance to be struck between portability and leveraging the unique innovations of each cloud platform.

How to make it happen?

Some key practices:

1. Define communication standards (ex: REST, gRPC, AsyncAPI)
2. Use open data formats (ex: JSON, Avro, Parquet)
3. Containerize applications for deployment portability
4. Abstract provider-specific SDKs behind generic interfaces
5. Implement service discovery and API gateways
6. Deploy and configure via Infrastructure-as-Code tools like Terraform
7. Use portable CI/CD platforms (ex: Jenkins, GitLab, Spinnaker)
8. Avoid non-portable services (ex: CloudFormation, Cloud Functions)

Enable portability one app/service at a time. It doesn't have to be all-or-nothing.

What are some gotchas?

• Not all services map 1:1 across cloud providers. Compromises may be required.
• Refactoring apps for portability can be a major undertaking. Start small.
• Secrets management, IAM policies, networking config etc. can vary widely between clouds.
• Data gravity can make moving large datasets prohibitively expensive. Consider this upfront.
• Optimizing for portability can negatively impact performance. Measure to find the right balance.

What are the alternatives?

If cross-cloud portability is not a hard requirement, consider:

• Standardizing on the cloud-native services of a single provider. This unlocks their latest innovations.
• Using a 3rd party multi-cloud management platform like Anthos, VMware Tanzu, or Red Hat OpenShift instead of managing portability yourself.
• Splitting different workloads across providers instead of spanning individual apps.

Explore Further

• CIS Controls v8 7.3 / 7.5 - Data Governance Cover data exchange and portability

This is certainly a complex topic but hopefully this gives a pragmatic overview of interop/portability policies, why they matter, and how to implement them. Let me know if you have any other questions!

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