Octavia RESOLVED as a clean negative. The chain audit flagged that
octavia-pki.yaml lands last and writes the same applications.octavia.options
map as the vips overlay, so under replace semantics octavia would lose its
vip and prefer-ipv6 with every offline gate still green. Researched against
source: juju 3.6 pins charm v12.1.1, and mergeStructs does
dstMap.SetMapIndex(srcKey, srcMapVal) per key for map-kind fields.
ApplicationSpec.Options is a Go map, so it deep-merges -- both overlays' keys
survive. The merge path is byte-identical between 2.9 and 3.6. The checker's
"MIRRORS juju's documented merge" comment is now sourced rather than assumed.
Logged: LP #2002371 (Triaged/High, unfixed) -- an EMPTY/null options: key
WIPES the base map rather than merging. Our overlays lack that shape and
nothing gates against acquiring it.

R1 AUTHORED. modules/node-vm gains osd_disk_size_bytes, default 0 = creates
nothing; the volume is count-gated and the disk entry appended via concat, so
an opted-out node has no extra resource and no plan diff -- precondition 4
verbatim. Four storage nodes per DC set osd_gib = 500: 8 volumes, not 18.
500 GiB is D-121's own budgeted figure (4x500Gi/DC = PASS, 5.31 TiB margin),
and D-121 records that footprint as an assumption pending an OSD-sizing
decision, so it is evidenced but not separately ruled. Headroom caveat
surfaced: dc0 has 2.0T available against 2.0 TiB nominal -- thin-provisioned,
so creation is cheap, but there is no room for those OSDs to fill.

D-104 AUTHORED. A 10th keyed entry per root, <dc>-juju-01, planning 1 add /
0 change / 0 destroy. The nine role nodes are untouched. 8 GiB / 4 vCPU are
the values the capacity gate actually modelled; disk 100 GiB is the authoring
value the amendment left open. MACs deliberately empty -- correct only before
enlistment, and they must be pinned from measurement after the first apply or
this reproduces the 2026-07-21 MAC-regeneration trap.

NEITHER IS APPLIED. opentofu-validate PASS on both roots; no apply run. Both
are live substrate mutations and individually operator-gated.

R1 precondition 3 is NOT satisfied and I am not treating it as such: the
amendment requires verifying BEFORE the apply that re-commissioning preserves
the D-134 statics and pinned MACs, and that needs live MAAS, absent here.

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