Cost Allocation & Showback Platform  ·  View 12 of 22  ·  5 · Runtime

Allocation Run

A pure function of three pinned inputs, made idempotent by a digest and gated by reconciliation.

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Scheduler Run orchestrator Snapshot service Policy registry Allocation runner Fact store Statement publisher 1. start run (period, mode) 2. pin billing snapshot 3. billing_snapshot_id 4. pin ownership as-of 5. ownership_snapshot_id 6. resolve active policy 7. policy_version_id 8. compute run digest 9. digest already present? 10. no - proceed 11. execute (3 pinned ids) 12. direct attribution 13. apportion shared pools 14. amortise commitments 15. compute remainder 16. write allocated facts 17. row count + digest 18. reconcile to invoice 19. variance over tolerance 20. run ready to freeze 21. statements v1 published Allocation Run — A Pure Function of Three Pinned Inputs Steps 8 to 10 make the run idempotent: an identical digest returns the existing result instead of recomputing it. Step 19 blocks publication rather than publishing a number that does not reconcile. v 1.0 · owner Platform Architecture · date 2026-09

The contract

  • Pin the billing snapshot, the ownership snapshot and the policy version before any arithmetic happens
  • Hash the three into a run digest; an identical digest returns the existing result rather than recomputing
  • Identical inputs produce bit-identical output — this is what makes any past figure defensible

Where it refuses

  • Reconciliation outside tolerance blocks publication rather than publishing a number that does not match the invoice
  • A degraded telemetry window marks the affected allocations degraded and excludes them from chargeback

Targets

  • Full month-to-date re-run p95 ≤ 45 min, hard ceiling 90 min, regardless of position in the month
  • Runs on interruptible batch capacity; a lost worker re-runs its partition, not the period
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Solution Architecture v1.0 · Microsoft Azure · Cost & Efficiency Architecture · 2026-0912-allocation-run-sequence