Operator utterance, verbatim: 'Set it false on the seven, keep every v6 VIP leg
(Recommended)'. Standing context from the same exchange: 'We have DC1 to stand
up with the IPv6 configuration changes. Lets continue with the IPv4/6 stand up
on DC0. We will fold in all lessons learned from the DC0 stand up into the DC1
stand up.'

Recorded as a D-101 RULING NOTE 2026-07-31 (b). OPS under GA-R3, no D-number;
D-101's matrix is UNAMENDED and every dual-family VIP is retained. It supersedes
the emission half of note (a) and now covers all thirteen apps.

Measured cause: get_relation_ip() returns early with get_ipv6_addr()[0] when the
option is true, and the LXD containers hold ONLY a link-local v6 while the HOSTS
are fully dual-stacked.

Why this is not abandoning v6: the option is a unit ADDRESS-FAMILY switch, not a
listener switch. HAProxy's :::port bind is gated on the kernel sysctl and
pacemaker selects IPv6addr by family detection. Neither consults it.

HONEST RESIDUAL, recorded not glossed: pacemaker will place a v6 VIP on a
container whose eth0 has no global v6, and whether that leg is ROUTABLE is
UNVERIFIED. Not a regression -- true today -- but it is what the v6 completion
work must close.

GATE CONSEQUENCE: invariant 9b coupled the option to the v6 legs for declaring
charms and would now FAIL. It is RE-POINTED to the new invariant and re-proven,
never deleted; when IPv6 becomes operational it returns to its coupling form and
this note records why it left.

Committed and pushed BEFORE the dependent work.

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