Session changelog (GA-R2/D1: ONE per session). Branch dc-dc-stage5-preconditions. Session open reconciled at HEAD c620f99: repo-lint 0 fail / 1 legacy warn, ledger-scan 3 open decisions / 28 open SEC / next-free D-141, DOCFIX-208, BUNDLEFIX-053. Status claims live in docs/CURRENT-STATE.md ONLY.
Scope: the item both the 2026-08-02 (part 2) close and docs/CURRENT-STATE.md name as the next session's FIRST item -- the preflight-P2 / phase-4 machines-overlay asymmetry -- worked to completion ahead of the bundle deploy.
WHAT WAS WRONG. runbooks/dc-dc-phase4-juju-bundle-per-dc.md told the operator to deploy vr1-dc0 as bundle.yaml + vr1-dc0-vips.yaml + vr1-dc0-octavia-pki.yaml, omitting overlays/vr1-dc0-machines.yaml. Its stated reason -- "there is no overlays/vr1-dc0-machines.yaml" (:527-528) -- had been FALSE since 2026-07-29, when that file was created (changelog-20260729 item 3.8). scripts/preflight.sh:144-145 folds the file into the merged input that gate P2 validates, so P2 was grading an input the deploy would not have passed.
WHY IT WAS NOT HYGIENE. The classification carried into this session was "DOCFIX-shaped ... likely bundles with the outstanding D-138 run-location DOCFIX" (changelog-20260802-queued-items item 5, finding 2). That is too low: the disputed artifact is the argument list of the very next live mutation. Executed as written, a dc0 deploy would have taken TWO independent injuries, neither of which surfaces as a deploy error:
bundle.yaml:494 states bridge-interface-mappings "IS NOT IN THIS FILE, and must never be re-added here" -- the overlay is its ONLY source. ovn-chassis would deploy with no br-ex mapping and tenant networks would come up with no external path. This is exactly the defect the 2026-07-29 move out of the base bundle was made to fix, reintroduced by stale prose.openstack-origin + 3 ceph source at the in-DC mirror. Without it those charms fetch ubuntu-cloud.archive.canonical.com, MEASURED UNREACHABLE from a node (000) under the D-107 airgap -- a failure at package-install time.MEASURED, NOT REASONED. Deep-merging bundle.yaml against the overlay:
overlay top-level keys: ['applications'] <- NO machines: block at all
apps in overlay: 16
ovn-chassis.bridge-interface-mappings: ADDS
barbican / magnum / octavia / ceph-mon / ceph-osd / ceph-radosgw : OVERRIDES (6)
cinder, designate, glance, keystone, neutron-api, nova-cloud-controller,
nova-compute, openstack-dashboard, placement : ADDS (9)
base ovn-chassis options: {'ovn-bridge-mappings': 'physnet1:br-ex',
'prefer-chassis-as-gw': True}
THIS CORRECTS THIS REPO'S OWN EARLIER FINDING (GA-R1 C2). docs/CURRENT-STATE.md recorded 2026-07-31 that "the only delta it makes to the merged input is ovn-chassis.options.bridge-interface-mappings". That was TRUE WHEN TAKEN and was overtaken HOURS LATER IN THE SAME SESSION by the UCA build. Sixteen applications, not one. The correcting capture is folded into the same CURRENT-STATE entry rather than replacing it.
THE FILE NAME IS WHAT MISLED THE RUNBOOK. dc0 genuinely needs no machines RETAG -- bundle.yaml's machines block already reads tags=openstack-vr1-dc0,<role> -- and the old table row said so correctly. The error was concluding from that true fact that the FILE is unnecessary. The overlay is the per-DC HAND-MAINTAINED overlay and its applications: half is load-bearing; its own header says so and says not to add a machines: block for symmetry.
WHAT CHANGED (runbooks/dc-dc-phase4-juju-bundle-per-dc.md, 6 sites):
overlays/${DC}-machines.yaml, REQUIRED for BOTH DCs, with the measured 16-app delta and the reason the old reading was wrong.vr1-dc0" paragraph replaced. The never-silently-skip-an-overlay rule is KEPT (it is right, and it is why a dc1 deploy cannot merge dc0 tags); only its dc0 exemption goes.--dry-run.applications.options merge).NOT CHANGED, because it was already right: scripts/preflight.sh P2 and runbooks/phase-01-bundle-deploy.md:199-201 both assemble the three-overlay set behind a [ -f ] guard. This was one wrong surface, not two disagreeing.
git revert this commit. The runbook returns to a dc0 command that omits a required overlay -- do not revert without also re-opening the finding in docs/CURRENT-STATE.md.The standing rule that a checker which cannot fail is not a gate applies to the gate as much as the command. Step 4.2's four gate items read the machines block, the machine count, the VIP prefixes, and overlay-path errors. The machines overlay's entire payload is under applications:, so all four would have passed a dc0 deploy with no provider bridge mapping and 15 unreachable package sources. Two added:
ovn-chassis shows THREE options, not one. bridge-interface-mappings must appear ALONGSIDE ovn-bridge-mappings: physnet1:br-ex and prefer-chassis-as-gw: true. This is the VERIFY-LIVE assertion both overlays' headers demand and that NO offline check can make: provider-bundle-check.py's _deep_merge merges key-by-key BY CONSTRUCTION, so validating through it cannot distinguish a key-by-key merge from a map REPLACE. Only the live dry-run can. If only the new key appears, the physnet mapping and the B2 gateway-chassis election are both gone from the deploy input and provider egress dies by a different route than the defect item 1 fixes. Also: exactly TWO MACs, a third means a wrong node.Item 6 -- every openstack-origin / ceph source resolves to an address this DC's nodes can reach. Names dc1's deliberate absence of the block as D-135's experiment RESULT, so a later reader does not "fix" the asymmetry.
Revert: delete gate items 5 and 6. Not recommended -- they are the only assertions in the chain that can see this overlay's payload.
runbooks/phase-00-teardown-maas-reset.md:233 runs provider-bundle-check.py with the vips overlay ONLY, so it grades a narrower input than either preflight P2 or the deploy command. Not deploy-blocking (teardown-time check), DOCFIX material for the same fold. Recorded in docs/CURRENT-STATE.md, not actioned here.
Gates at delivery: bash scripts/repo-lint.sh -- 0 fail, 1 warn (the legacy D-001..018 ASCII carve-out), 658 files. No script changed, so no harness is implicated; the gauntlet's last full run stands at ALL GREEN (98) from the 2026-08-02 (part 2) close.