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Architecture Decision Records

Significant decisions in TAPPaaS are made in writing, before the code: each one is an Architecture Decision Record (ADR) in this directory, and it stays here forever — superseded ADRs are marked, never deleted. If you want to know why the platform is the way it is, this is the trail.

The 2.0 spine — the taxonomy family

ADR Decides
ADR-007 — TAPPaaS Taxonomy The model everything hangs on: one Site, three classification domains (People · Apps · Environments), Health as a cross-cutting lens. Detailed per domain in sub-ADRs 007a–007e, realization (managers/controllers) in 007f.
ADR-009 — Composition Meta-Model How a deployable unit is built (module = atomic deployable unit; <module>:<service> coordinates) — composition, as distinct from ADR-007's classification.

Platform decisions

ADR Decides
ADR-001 — Trunk-mode VLAN connectivity VMs attach on trunk ports; zones are VLANs.
ADR-002 — Dynamic VLAN configuration Zone/VLAN wiring happens at deploy time, driven by module config.
ADR-003 — Dependency management Modules declare dependsOn; install order is derived, never hardcoded.
ADR-004 — Module catalog & config cascade Where module configuration comes from and how overrides cascade.
ADR-005 — Variant domain architecture Superseded in practice by the ADR-007 Environments model (variants → environments).
ADR-006 — Identity: users and roles The identity model behind SSO (Authentik) — users, groups, roles.
ADR-008 — Switch module / network infrastructure Physical switches and APs become managed parts of the platform.
ADR-010 — VPS satellite The optional off-premises satellite: public ingress, off-site backup, admin VPN.
ADR-012 — Backup enhancement The managed backup-policy model (site → environment → module cascade).

Governance

ADR Decides
ADR-011 — SBOM Governance Per-module software bill of materials (CycloneDX) for CVE tracking.
ADR-013 — Documentation Structure and Standards Where documentation lives, which artifact serves which audience, and how the site syncs from source.

Writing a new ADR? Decide in writing first, before the code; the process and standards are in ADR-013 — Documentation Structure and Standards.