jakman85andClaude Opus 5
b258e47aa6
The claim this branch originally shipped (a node cannot reach a LoadBalancer VIP whose Cilium L2 announcement lease it holds, so VPN clients inherit that via hostNetwork MASQUERADE) is FALSE. Re-measured with all 8 l2announce leases on k3s-prod-1: ip neigh show 192.168.2.20 -> INCOMPLETE (cause present) nc -z 192.168.2.20 443 -> OK curl --resolve ... :192.168.2.20 -> 200 in 25ms (effect absent) Cause present, effect absent. prod-2 and prod-3 return the same 200. Why it was never going to bite: cilium-dbg status shows `KubeProxyReplacement: True [eno1 ..., wg0 10.90.0.1]` and `Masquerading: BPF [eno1, wg0]` -- Cilium's LB datapath is attached to wg0, so a client packet for a VIP is DNAT'd in BPF BEFORE any neighbour lookup, and the Gateway backend is a node-local Envoy socket anyway. The methodological error, which is the part worth keeping: every probe was run from the wireguard pod on the grounds that sharing the host netns made it "the path a MASQUERADEd client takes". False. A MASQUERADEd client is FORWARDED (netfilter FORWARD + routing); a probe started in the pod is SOCKET-ORIGINATED (Cilium socket-LB). Different hooks -- sharing a namespace is not sharing a hook. The `curl --interface wg0` control cited to rule out a host-netns artefact fails on ALL THREE nodes including ones whose ARP resolves, so it discriminated nothing. A raw-IP `curl -k https://192.168.2.20/` returning rc=35 is missing SNI, not unreachability. Also corrected: new-peer.sh emits AllowedIPs = 0.0.0.0/0 (FULL tunnel) by default; `--split` is the opt-in. An earlier reading had the branches backwards. All code is withdrawn -- the nodeSelector exclusion, the node_baseline label tasks, both alerts, the promtool tests and the KSM allowlist entry are gone. Net change is three documentation files, purely additive (356 insertions, 0 deletions), recording what was measured so the next person does not redo it. The reported internet-routing problem is NOT diagnosed here: no client had connected since the power-cycle (no peer endpoint, 0 packets through FORWARD and MASQUERADE), so the forwarded path was unmeasurable. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
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 (required by CLAUDE.md §0) 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.