Autoscaling Controller  ·  View 28 of 37  ·  5 · Operations

Multi-Region Topology

Two identical control planes that share intent and nothing else.

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Region A · Sweden Central Control plane Full Control Plane 2,000 targets Regional State no remote read Managed fleet 200k Instances design ceiling Region B · West Europe Control plane Full Control Plane identical build Regional State no remote read Managed fleet 200k Instances Global · declarative and reporting only Intent Policy Repository reviewed, versioned Argo CD per-region sync Evidence Fleet Cost View async, lagging Fleet SLO View never a dependency declared config declared config export export Multi-Region — Independent Control Planes Application we own Data store External / third party Security / platform batch event / async Adding a region is a deployment, not a design change. Region B failing entirely has no effect on Region A's control loop. v 1.0 · owner Data & AI Global Practice · date 2026-09

Decisions

  • Each region runs a full, independent control plane. There is no primary and no failover.
  • Global views are reporting only and lag deliberately, so no one is tempted to make them a dependency.
  • Region B failing entirely has no effect on Region A's loop, because there is no path between them.

What is global

  • The policy repository and the identity provider. Both are declarative and both are off the control path.
  • Argo CD syncs each region separately, so a bad policy reaches one region before the next.

Risks

  • Entra ID is a genuine global dependency for token issue. Tokens are cached for their full hour, so a short outage is survivable and a long one degrades to fail-static.
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Solution Architecture v1.0 · Data & AI Global Practice · 2026-09 · 37 views · Azure and open source28-multi-region-topology