CI/CD Platform  ·  View 07 of 22  ·  Structure

Layered Architecture

Seven layers, with admission above the control plane because classification is a one-time act.

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Experience Run console live tail Public API CLI local repro Checks on the diff Admission Event receiver Definition compiler Policy admission Trust classifier Control plane Run state machine Fair scheduler entitlements Gate decision service Secret broker Attestor Execution plane Sandbox manager Warm pool Isolation hosts microVM per job Per-job agent Egress proxy Evidence & artefacts Artefact store immutable Build cache Transparency log append-only Log store hot to cold Delivery Environment registry Deployment lock Deployers Rollback controller Foundation Run metadata store Run event log Key store hardware-backed Identity federation trust class job + lease observed inputs evidence CI/CD Platform — Layered Architecture Application we own Interface / broker Security / platform Decision point Data store Queue / topic synchronous Admission sits above the control plane because classification happens once, before any capacity is committed, and cannot be revised later. v 1.0 · owner Platform Engineering · date 2026-09

Why this order

  • Admission sits above the control plane because it happens once, before capacity is committed, and produces a fact — the trust class — that everything below consumes and nothing below may revise.
  • The execution plane sits below the control plane and is treated as untrusted by it: results travel up as reports to be validated, never as assertions to be believed.
  • Evidence and artefacts sit below execution because they are written by it and read by delivery, which is the only path by which a build's output reaches production.

Deliberate omissions

  • Four edges are drawn out of the dozens that exist; the rest follow the layering. The four shown are the ones that cross a trust boundary.
  • The dependency mirror and cache appear in the evidence layer for simplicity; they are disposable and are separated properly in view 11.

Risks

  • Five control-plane services on the critical path of every job. Each one added raises the availability the layer as a whole must hold.
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Solution Architecture v1.0 · Amazon Web Services · Platform Architecture · 2026-0907-layered-architecture