Deploying an AI Governance Proxy Active-Active Across Multiple Regions
An active-active AI governance proxy deployment runs full enforcement in every region at once. Each region evaluates policy locally, from a versioned policy bundle distributed by a central control plane.
- Traffic is routed to the nearest healthy region.
- Fast-changing state such as rate limits is reconciled loosely, while policy, identity, and revocation data are distributed with strict versioning.
- When something fails, the proxy denies traffic instead of bypassing enforcement.
- Each region writes its own tamper-evident audit records, and a federated index supports investigation across regions.
Reference architecture: central control plane, regional enforcement
A governance proxy sits on the critical path for model, tool, and Model Context Protocol (MCP) traffic. The simplest durable design separates what is decided centrally from what is enforced regionally. Regions should keep enforcing even if the control plane is unreachable, within limits you define.
- Regional data plane
- Regional state store
- Regional audit pipeline
- Regional data plane
- Regional state store
- Regional audit pipeline
Components
- Control plane. Authors policy, manages agent identities and permission scopes, and publishes signed, versioned bundles. It is not on the request path.
- Regional data plane. Proxy instances that evaluate every request against a locally cached bundle. Instances stay stateless where possible so any instance can serve any request.
- Distribution layer. Delivers bundles and revocations to each region and reports which version each region is running.
- Regional state store. Holds counters and session data that need low-latency reads, scoped to the region.
- Regional audit pipeline. Writes decision records to local append-only storage before forwarding indexes elsewhere.
- Egress controls. Network rules that let agents reach models and tools only through the proxy in any region.
- Testing and rollout sequence.
Design decisions in a multi-region governance proxy
| Area | Design decision |
|---|---|
| Routing | Send traffic to the nearest healthy region without creating a path around the proxy. |
| Policy and identity | Distribute versioned bundles and agent permissions from one control plane. |
| Failure behavior | Define fail-closed defaults per traffic type before an outage occurs. |
| Audit | Keep records in the region of origin and make them searchable across regions. |
Traffic routing and failover for streaming and agent sessions
Traffic is routed to the nearest healthy region. Routing must not create a path around the proxy, so egress controls let agents reach models and tools only through the proxy in any region. Because each region evaluates policy locally and instances stay stateless where possible, any instance can serve any request.
State consistency: match the model to the risk
Not all state needs the same consistency. Fast-changing state such as rate limits is reconciled loosely, and counters and session data are held in a regional state store scoped to the region. Policy, identity, and revocation data are distributed with strict versioning, and the distribution layer reports which version each region is running.
Failure modes: fail closed by default
When something fails, the proxy denies traffic instead of bypassing enforcement. Regions keep enforcing from their locally cached bundle even if the control plane is unreachable, within limits you define.
Audit aggregation that is tamper-evident and residency-aware
Each region writes its own tamper-evident audit records. The regional audit pipeline writes decision records to local append-only storage before forwarding indexes elsewhere, so records stay in the region of origin. A federated index makes them searchable across regions and supports investigation.