Translate sovereignty into requirements.
Start with specific requirements for ownership, administration, location, identity and network access. These requirements should drive deployment choices and verification.
Local hardware alone does not establish isolation, regulatory compliance or suitability for sensitive workloads. Those properties require an assessed configuration and operating controls.
Make connectivity a deliberate choice.
Identify every external dependency, update mechanism and remote service. Determine which are permitted and how the deployed environment will behave when they are unavailable.
Federate within declared boundaries.
If clusters connect across locations or organizations, define the authorized workload and data movement for each relationship. Federation should preserve the distinctions the deployment is required to uphold.