Files
home-network-k3s-impl/decisions
jakman85andClaude Opus 5 f92707f38c
gate / gate (pull_request) Successful in 1m47s
gate / conformance (pull_request) Has been skipped
feat(vpn-ingress): WireGuard remote access on udp/51820 (hostNetwork, declarative peers)
Lets the operator's Android / Linux / Windows / macOS devices dial in from
anywhere and behave like LAN machines: full reach to 192.168.2.0/24 plus
internet egress out the house WAN. Opposite direction to platform/vpn-egress,
which sends pods OUT through PIA; the two share nothing but the word "VPN".

WireGuard because it is the only option with a first-party client on all four
named platforms, and because its handshake MAC is keyed with the responder's
own public key: an unauthenticated packet gets NO reply, so udp/51820 is
indistinguishable from a closed port. That, not "it is encrypted", is what
makes an unfiltered WAN port defensible, and why there is no source allowlist.

hostNetwork: true is REQUIRED, not convenient. A pod-networked server must SNAT
clients to its own pod IP, so every remote client would carry that pod's Cilium
identity -- and a pod-sourced request to the shared Gateway VIP returns 403 from
Envoy for ALL 16 hostnames (measured 2026-10-04), because Cilium's Gateway
preserves the original source identity and enforces the destination's ingress
policy. The obvious build would have shipped a healthy-looking tunnel on which
every cluster web UI was 403 and *.home.keithjackson.dev did not even resolve.
In the host netns traffic is SNATed to the node and arrives as host/remote-node,
exactly like a LAN client. It also sidesteps the unsafe ip_forward sysctl, the
L2-announcement lease lottery, and double encapsulation (hence MTU 1420).
Permitted by restrict-host-namespaces' own carve-out for platform namespaces.
The cost is stated in networkpolicy.yaml rather than papered over: no
NetworkPolicy constrains a hostNetwork pod.

A DaemonSet so the hand-made WAN forward cannot be invalidated by a reschedule;
all three nodes answer the same keys, so failover is a one-line router change.

Peer PUBLIC keys are plaintext in peers.yaml, which makes "who can get into my
house" a reviewable PR diff. The only secret -- the server's private key -- is
an out-of-band Secret: an agent must not mint a long-lived private key, and the
two halves are joined only at pod start into a tmpfs that dies with the pod.

Ships INERT-BUT-HEALTHY with zero peers. THREE off-repo manual steps remain
(kernel module, server key, WAN forward) -- runbooks/vpn-remote-access.md.

Touches clusters/** , so ci/approval-policy.sh will block pending the
operator's /approve-override. Deliberately not posted by me (CLAUDE.md §1).

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
2026-10-05 22:29:46 -05:00
..

decisions/ — the handoff log, one file per entry

This directory is the decision log. ../DECISIONS-LOG.md is the frozen archive of everything written before 2026-09-29 and is never edited again (see "The archive is frozen" below).

Why this exists

DECISIONS-LOG.md was append-only in a single file, and every agent appended to its tail. Two branches that both append hit the same last hunk, so git cannot auto-merge them: the second one to be reviewed conflicts, and so does the third, and the fourth. Measured on 2026-09-29: four of the five open PRs were unmergeable, and DECISIONS-LOG.md was the only conflicting file in all four:

#22 fix/crafty-oauth2-proxy-signin      CONFLICT (content): DECISIONS-LOG.md
#20 feat/conformance-job-template       CONFLICT (content): DECISIONS-LOG.md
#19 feat/conformance-trigger-kubeconfig CONFLICT (content): DECISIONS-LOG.md
#18 feat/conformance-runner-image       CONFLICT (content): DECISIONS-LOG.md
#17 feat/ci-is-the-approver             clean  (it touched no log entry)

Nothing was wrong with any of those changes. The log's storage format serialised work that was otherwise parallel, and it got worse with every concurrent branch: N branches produce N-1 rebases, each of which invalidates any gate run that preceded it.

The fix is the obvious one for concurrent appenders: stop sharing a file. Each handoff is its own file. Two agents writing handoffs touch disjoint paths, so there is nothing for git to merge and nothing to conflict. This scales to any number of parallel branches with zero coordination — which is the point, since the agents are deliberately isolated from each other in separate worktrees and cannot coordinate.

There is deliberately no index file and no counter. An index would be a shared mutable file — exactly the thing that just failed — and a sequence number would have two agents racing for 0043. The directory listing is the index.

Writing an entry

One file per handoff, named:

decisions/YYYY-MM-DD-<slug>.md

<slug> is lowercase [a-z0-9-]. Use your branch name's last segment — it is already unique per unit of work, which is precisely the property the filename needs. A branch fix/crafty-oauth2-proxy-signin handed off on 2026-09-29 writes:

decisions/2026-09-29-crafty-oauth2-proxy-signin.md

The file is YAML frontmatter followed by three required sections:

---
date: 2026-09-29
branch: fix/crafty-oauth2-proxy-signin
title: The Keycloak gate works — Crafty's own login was the wall
---

## What changed

Prose. What you actually did, and why.

## What I verified

The measurements, with their numbers. Quote the field you read, not the prose you
believed. Name the gate result and its exit code.

## What I did NOT verify

Everything else. An honest "UNVERIFIED" is worth more than an optimistic "green" —
this repo has been burned by the difference more than once.

All three headings are required and enforced (ci/decisions-log.sh). They are CLAUDE.md §7's contract; making them a checked structure is what stops an entry degrading into "done ✅".

Reading the log

The whole log, oldest first:

ls decisions/[0-9]*.md | sort

The current PM handoff — the newest entry. Ties within a day are broken by what landed on main last, which is the honest answer, so ask git rather than the filename:

git log --diff-filter=A --format='%H' --name-only -- 'decisions/[0-9]*.md' \
  | grep '^decisions/' | head -1

For a quick skim of who said what:

grep -H '^title:' decisions/[0-9]*.md | sort

The archive is frozen

DECISIONS-LOG.md is read-only history. Its SHA-256 is pinned in decisions/ARCHIVE.sha256 and ci/decisions-log.sh fails the merge gate if the file changes. That is not ceremony: without it, the next agent to read runbooks/ or an old CLAUDE.md habit appends to the tail again and re-creates the conflict for everybody else, silently, one PR at a time.

If the archive genuinely must change (a leaked credential to redact, say), that is a deliberate, reviewed act: change it, run sha256sum DECISIONS-LOG.md > decisions/ARCHIVE.sha256, and say in your handoff entry why. Re-pinning is visible in the diff. Appending is not.