Files
home-network-k3s/decisions/README.md
jakman85andClaude Opus 5.5 250fb54154 docs: bring the specification in line with the accepted implementation
The operator ruled the implementation repo's main (50c8719) the latest
and accepted state. Sync the spec to it.

Accepted changes are reflected: one bare-metal environment, TrueNAS bulk
storage, R2 off-cluster backup, CloudNativePG, single-node VPN gateway
with Cilium fail-closed, inbound WireGuard, per-app auth sidecars,
Renovate, the CI gate as approver, and the pm-agent. New ADR-0017..0025;
ADR-0016 corrected and accepted; R-* IDs unchanged, eight amended.

Where the implementation has simply not met a requirement, the
requirement stands and the shortfall is recorded in docs/16-known-gaps.md.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
2026-11-08 22:46:00 -06:00

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5.8 KiB
Markdown

# Architecture Decision Records (ADRs)
ADRs are an **append-only ledger** of the significant technology and pattern choices for this
platform. Each records the context, the decision, the rejected alternatives, and the requirements it
serves. **Do not edit an accepted decision in place** — supersede it with a new ADR.
> **ADRs are specifications and are immutable to AI agents** (R-TEST-06). Agents may *draft* a
> proposed ADR and escalate it, but only the **human operator/architect** approves/accepts or edits
> ADRs. See [`../AGENTS.md` §3 and §11](../AGENTS.md).
**These ADRs are not the implementation's handoff log.** The dated files in the
[implementation repo](https://gitea.home.keithjackson.dev/Home-Network/home-network-k3s-impl)'s `decisions/`
directory record what each change did and how it was verified. ADRs here record locked technology and
pattern choices.
**Partial supersession.** When a new ADR replaces only part of an accepted one, the older ADR stays
`Accepted` and its Status line names the clause superseded (the ADR-0013 precedent).
## Process (read before proposing a change)
1. To change a decision, create a **new** ADR with the next number and set `Status: Proposed`,
`Supersedes: ADR-XXXX`. (Agents draft + escalate; the human approves.)
2. State what new information invalidates the old decision.
3. On approval, set the new ADR `Accepted` and the old one `Superseded by: ADR-YYYY`.
4. Never silently re-interpret an accepted ADR (see [`../AGENTS.md` §3](../AGENTS.md)).
## Template
```markdown
# ADR-XXXX — <title>
- Status: Proposed | Accepted | Superseded by ADR-YYYY
- Date: <YYYY-MM-DD>
- Serves: <requirement IDs, e.g. R-NET-01, R-NET-06>
- Supersedes: <ADR-ZZZZ or —>
## Context
<forces, constraints, why a decision is needed>
## Decision
<what we chose, stated decisively>
## Alternatives considered
<options and why rejected>
## Consequences
<positive, negative, follow-ups, risks>
```
## Index
| ADR | Title | Status | Serves |
|---|---|---|---|
| [0001](adr-0001-kubernetes-distribution-k3s.md) | Kubernetes distribution: k3s | Accepted — dev provisioning clause superseded by 0017 | R-PLAT-01 |
| [0002](adr-0002-cni-cilium.md) | CNI & network policy & ingress: Cilium + Gateway API | Accepted | R-NET-01..07, R-DNS-01 |
| [0003](adr-0003-storage-longhorn.md) | Distributed storage: Longhorn (+ bulk tier, Velero) | Accepted — backup and bulk-backing clauses superseded by 0018 | R-STATE-01..04 |
| [0004](adr-0004-gitops-flux.md) | GitOps engine: Flux CD | Accepted | R-GITOPS-01..03 |
| [0005](adr-0005-vm-workloads-kubevirt.md) | VM workloads: KubeVirt + CDI | Accepted | R-PLAT-03 |
| [0006](adr-0006-tls-cert-manager-letsencrypt.md) | TLS: cert-manager + Let's Encrypt (DNS-01) | Accepted | R-TLS-01..03 |
| [0007](adr-0007-secrets-sops-age.md) | Secrets: SOPS + age | Accepted | R-SEC-01 |
| [0008](adr-0008-vpn-egress-model.md) | VPN egress model: Gluetun sidecar + Cilium Egress Gateway | ~~Superseded by 0012~~ | R-NET-05/06 |
| [0009](adr-0009-automated-image-updates.md) | Automated updates: Flux image automation + Renovate | ~~Superseded by 0023~~ | R-UPD-01..03 |
| [0010](adr-0010-conformance-testing.md) | Conformance testing: automated, reproducible, behavior-based | Accepted | R-TEST-01..06 |
| [0011](adr-0011-test-tooling-kyverno-chainsaw.md) | Conformance test tooling: Kyverno + Chainsaw | Accepted | R-TEST-01..05 |
| [0012](adr-0012-vpn-egress-single-expressvpn-gateway.md) | VPN egress: single shared in-cluster ExpressVPN gateway | ~~Superseded by 0013~~ | R-NET-05/06/07 |
| [0013](adr-0013-vpn-provider-pia-gluetun-wireguard.md) | VPN provider: PIA over OpenVPN-UDP + port forwarding | Accepted — provider/protocol only (client+steering superseded by 0015) | R-NET-05/06/07 |
| [0014](adr-0014-idp-keycloak.md) | Identity Provider: Keycloak (SSO via OIDC + forward-auth) | Accepted — forward-auth enforcement point and app list superseded by 0022 | R-IDP-01..06 |
| [0015](adr-0015-vpn-egress-steering-node-tunnel-cilium.md) | VPN egress steering: node-level tunnel + Cilium Egress Gateway (host kill-switch) | Accepted — Kill-switch and Resilience bullets superseded by 0020 | R-NET-05/06/07 |
| [0016](adr-0016-public-ingress-cloudflare-tunnel.md) | Public ingress: Cloudflare Tunnel (outbound-only) instead of edge port-forwarding | Accepted | R-DNS-01..05, R-TLS-01/02, R-SEC-02/04 |
| [0017](adr-0017-single-environment-bare-metal-production.md) | Single environment: bare-metal production; dev retired | Accepted | R-PLAT-01, R-ENV-01/02/03, R-STATE-01/02 |
| [0018](adr-0018-storage-backup-truenas-r2.md) | Storage and backup: TrueNAS NFS bulk tier; Velero/kopia + Barman to Cloudflare R2 | Accepted | R-STATE-03, R-STATE-04 |
| [0019](adr-0019-postgresql-cloudnativepg.md) | PostgreSQL via CloudNativePG | Accepted | R-IDP-05, R-STATE-01, R-STATE-02, R-STATE-03 |
| [0020](adr-0020-vpn-egress-single-gateway-cilium-fail-closed.md) | VPN egress: single gateway node, Cilium-enforced fail-closed | Accepted | R-NET-05, R-NET-06 |
| [0021](adr-0021-inbound-remote-access-wireguard.md) | Inbound remote access: WireGuard on a hostNetwork DaemonSet | Accepted | remote operator access (no dedicated requirement ID); bounds R-NET-01, R-SEC-02, R-SEC-04 |
| [0022](adr-0022-forward-auth-per-app-oauth2-proxy-sidecars.md) | Forward-auth via per-app oauth2-proxy sidecars | Accepted | R-IDP-02, R-IDP-06 |
| [0023](adr-0023-automated-updates-renovate.md) | Automated updates: Renovate for images and charts, every change PR-gated | Accepted | R-UPD-01, R-UPD-02, R-UPD-03, R-TEST-03 |
| [0024](adr-0024-delivery-authority-ci-gate.md) | Delivery authority: the CI gate is the approver; sensitive-path review; attributed admin override | Accepted | R-TEST-03, R-TEST-06, R-GITOPS-01, R-SEC-02 |
| [0025](adr-0025-in-cluster-ai-program-manager.md) | In-cluster AI Program Manager (pm-agent) | Accepted | R-GITOPS-01, R-TEST-03, R-TEST-06, R-SEC-02 |