Pre-deploy: rack input refreshed + hash-verified, preflight captured, dry-run green ...

(a) The dc0 rack's ~/repo-stage is a COPY, not a clone -- nothing updates it, and
it still held the pre-ruling vips overlay. Exactly one of four files differed;
copied, then ALL FOUR hash-compared against repo HEAD. The gitignored
octavia-pki overlay was deliberately not touched (SEC-029) and verifies
byte-identical at 5fc117f1, still 0600. A sweep is evidence about the deploy
only if the swept bytes ARE the deployed bytes.

(b) Preflight captured (242 lines, exit 1), run with
MAAS_PROFILE=vr1-dc0-region -- without it preflight is REGION-BLIND and emits 19
false negatives. Instrument proven current first: maas-profile-assert.sh
vr1-dc0-region hot-kid exits 0. P1-P4 and P7 PASS, incl. aligned VIPs 13 OK / 0
bad against the RE-RENDERED overlay. P5 FAIL, 11 findings.

(c) The P5 delta is ENUMERATED. The 2026-07-30 acceptance covered six findings
and says it covers "these six, enumerated, and nothing else". All six are still
present; FIVE NEW are all vr1-dc1 S2 rows (SEC-027/-028) -- the D-137 forward
register correctly reporting that dc1's region is not built. Diff appended to
the capture. Needs its own GA-R5 exchange before the deploy.

(d) Step 4.2 --dry-run against the fixed input: exit 0, 56 apps / 108 relations
/ 33 unit placements. The ceph-osd tags=openstack exposure is now MEASURED, not
reasoned: the plan places ceph-osd/0..3 on machines 5-8 by explicit id, so the
absent tag never has to match. The residual (a later UNPLACED add-unit) stands.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf

Fix a defect in my own build: invariant 9a was VIP-scoped and the charm list was short ...

Found by a repo-wide grep, not by any gate. Two faults, one cause -- I
measured and gated the population the QUESTION named (the 13 VIP charms)
rather than the population the INVARIANT covers (every application juju
validates).

(1) PREFER_IPV6_CHARMS was WRONG. Re-measured across ALL 33 charms in
bundle.yaml: TWELVE declare the option, not seven. The five missing are
ceph-mon 491, ceph-osd 953 (squid/stable), nova-compute 894, hacluster 166
(2.4/stable) and mysql-innodb-cluster 164 (8.0/stable).

(2) 9a was written INSIDE the VIP loop, so an application with no vip never
reached it -- and the repo ALREADY has that case:
overlays/dc-dc-ipv6-family-matrix.yaml sets prefer-ipv6 on ceph-mon, which
carries no VIP. That overlay is a LATER deploy step, so the miss would have
passed attempt 2 cleanly and surfaced at the step after, looking like a new
fault.

9a now runs over EVERY application, before the VIP loop; the VIP loop skips an
app 9a already flagged so the diagnosis is not doubled. ceph-mon's own in-file
claim of the option is now INDEPENDENTLY VERIFIED from the artifact rather
than taken from the comment.

Harness 48 -> 50/50. T47 (non-VIP app whose charm lacks the option FAILS) and
T48 (ceph-mon PASSES) both mutation-proven: re-scoping 9a back to the VIP loop
kills T47; dropping ceph-mon from the list kills T48.

Gauntlet ALL GREEN (93); repo-lint 0 fail.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf

Sweep both deploy inputs for option NAMES and VALUE TYPES: clean, and proven able to fail ...

The two extensions owed after the ruling, now run:
  dc0  75 assignments / 20 schemas / 0 unknown name / 0 type mismatch / 0 note
  dc1  75 assignments / 20 schemas / 0 unknown name / 0 type mismatch / 0 note
Both EXIT 0. dc1 introduces no new charm@channel pair -- checked, not assumed.

PROOF OF TEETH, because a clean sweep across two inputs is exactly the
implausibly-uniform result this repo has been burned by. Three defects planted
in a THROWAWAY copy, all three caught, EXIT 1:
  [FAIL name] barbican  does not declare option 'prefer-ipv6'   (attempt-1 defect)
  [FAIL type] keystone  'prefer-ipv6': declared boolean, got str ('true')
  [note]      glance    'vip': declared string, value is unquoted float

Type judgement is deliberately conservative: a mismatch is reported only where
juju's own coercion cannot save it. A scalar where a STRING is declared is a
NOTE, not a failure -- but it is still surfaced, because an unquoted value is
how a version string silently becomes a float. An UNRECOGNISED declared type
REFUSES rather than passing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf

Build the 2026-07-31 ruling: renderer + invariant 9 replaced, overlays re-rendered ...

Three parts, all mutation-proven.

(i) provider-bundle-check.py gains PREFER_IPV6_CHARMS -- the measured authority,
keyed by CHARM name, carrying the revisions and a re-measure warning -- and
invariant 9 is REPLACED, never deleted:
  9a  prefer-ipv6 on a charm that does NOT declare it FAILS. Asserted on
      PRESENCE, not truthiness: 'prefer-ipv6: false' is the same fatal
      'unknown option' to juju as true.
  9b  on a DECLARING charm it still travels with the v6 legs -- the L3-9
      protection is retained unchanged for those seven.
  9c  arity.
The old text's mechanism claim ("prefer-ipv6 makes HAProxy bind :::port") is
refuted by this session's measurement and is recorded as such in-file.

(ii) render-dc-overlays.py emits the option only for a declaring charm, READING
the set from provider-bundle-check with ast rather than restating it (the same
rule APP_OCTET already uses). render() keeps its purity property: the set is a
PARAMETER and the default REFUSES rather than defaulting to empty, because an
empty set renders a plausible artifact with the option nowhere. Both overlays
re-rendered: exactly SIX lines removed per DC and nothing else -- every vip
string byte-identical, so all v6 legs are retained.

(iii) tests/provider-bundle-check 44 -> 48/48. T43 reproduces the attempt-1
defect; T44 proves presence-not-truthiness; T45 is the positive control; T46
asserts the DIAGNOSIS.

MUTATION PASS -- six mutations, every one killed tests. And one NEW assertion
was found to be DECORATION and was REPLACED rather than kept: T46's first form
could not fail under any mutation, because a non-declaring charm with no option
reaches neither branch. Re-written to catch the fold-9a-into-9b simplification
and re-proven.

Gauntlet ALL GREEN (93); repo-lint 0 fail. The fixed dc0 deploy input now
sweeps CLEAN on option names: 75 assignments, 20 schemas, 0 unknown.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf

prefer-ipv6 research: size option (b) and scope the sweep claim ...

Two corrections to my own framing, both measured:

(1) Option (b) is NOT a values-file edit. 'prefer-ipv6: true' is INJECTED
UNCONDITIONALLY by scripts/render-dc-overlays.py:243-246 whenever fam ==
"dual", and 'family: dual' is a single TOP-LEVEL key in
render/values/vr1-dc{0,1}-vips.yaml:3 -- not per-app data. Implementing (b)
means teaching the renderer which charms declare the option, re-pointing
tests/render-drift, and replacing invariant 9: a code change with a harness.
Recorded before the fork is put to the operator so the ruling is taken on the
real cost.

(2) The option-name sweep's claim is scoped inline. It checked NAMES, dc0
only. Option VALUE TYPES (the 'type:' field in every schema already
downloaded) and the dc1 input are both owed before the redeploy, and each
could cost an attempt the same way.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf

prefer-ipv6 research DONE: the option never drove the v6 HAProxy bind ...

Answers the 2026-07-31 ruled question ("Research what those 6 charms do with
v6 VIPs first"). Measured by downloading each charm at its pinned channel for
amd64/ubuntu@22.04 and reading its templates and code -- not Charmhub's
config-yaml, which answers only whether the knob is declared.

FINDING: in BOTH template families the ':::port' frontend bind is gated on
ipv6_enabled = not is_ipv6_disabled(), a read of the kernel
net.ipv6.conf.all.disable_ipv6 sysctl -- MEASURED 0 on a live MAAS-deployed
jammy node in this DC. The v6 VIP is assigned by pacemaker on per-address
family detection. vault ships no haproxy template at all; its listener is the
hardcoded literal [::]:8200. prefer-ipv6 is a UNIT ADDRESS-FAMILY switch, and
the one value it sets that sounds like a bind address (haproxy_host) is
consumed by no template in any charm downloaded.

So option (b) -- drop the option from the six, keep their v6 VIP legs -- is
what the measurement supports. NOT TAKEN: the ruling is the operator's, the
overlay is untouched and R2 is unamended.

Also recorded: provider-bundle-check invariant 9's mechanism claim is wrong
and must be REPLACED (never deleted) when a ruling lands; a new and separate
question about the SEVEN charms that do declare the option; a full
option-name sweep of the dc0 deploy input (56 apps / 81 assignments / 20
schemas / 0 unresolvable) showing prefer-ipv6 on the six is the ONLY unknown
option, so nothing else is waiting for attempt 2; and a runbook defect --
the dc0 deploy block omits vr1-dc0-machines.yaml, which is NOT a no-op (it
carries ovn-chassis bridge-interface-mappings).

Read-only session: no cloud mutation, no overlay edit, no ruling adopted.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf