# Changelog 2026-07-09 -- Stage 7 runbook: Designate, COS, Magnum/CAPI (DOCFIX-159)

No live infrastructure touched -- new runbook document only. Authored by a
delegated subagent (general-purpose, briefed with this repo's discipline,
D-106/D-008/D-019/D-021/D-105/D-046, `bundle.yaml`, `phase-01-bundle-
deploy.md`, and `phase-06/07/08` as primary sources), reviewed before this
commit -- repo-lint was clean on the first pass.

## Item

### 1. DOCFIX-159 -- `runbooks/dc-dc-phase6-designate-cos-magnum.md`
FILES: `runbooks/dc-dc-phase6-designate-cos-magnum.md` (new), `docs/dc-dc-
deployment-workflow.md` (Stage 7 row updated).

WHAT: per-DC Designate reactivation (D-106, superseding D-019/reactivating
D-008), COS observability, and Magnum/CAPI, reusing `phase-06/07/08` by
filename rather than duplicating their content.

**Quotes, rather than paraphrases, the exact current repo state being
reversed:** `bundle.yaml`'s own D-019 comment line and `phase-01-bundle-
deploy.md`'s "NO designate (D-019)" gate text are both reproduced verbatim
before describing the reversal, so the diff is traceable to real text, not
a vague "add designate" gloss.

**Correctly identifies the reversal is bigger than one application:**
D-106's own reactivated bootstrap order includes `os-public-hostname` per
API charm as its second step -- directly reversing `bundle.yaml`'s
separate B5 posture ("IP-ONLY -- os-public-hostname dropped on all API
charms... No control-plane DNS dependency"). The runbook treats this as
two coupled changes under one D-106 umbrella (add designate; re-add
os-public-hostname fleet-wide) rather than quietly bundling it into a
one-line description, and proposes -- without silently adopting --
pushing the new per-DC FQDN literals into new `overlays/dc1-hostnames.yaml`
/`dc2-hostnames.yaml` files (mirroring the existing `octavia-pki.yaml`
overlay pattern) so `bundle.yaml` itself stays DC-agnostic.

**D-046's domain-setup trap is quoted verbatim twice** (a top-of-file
`!!!` callout and again inline at the Magnum step) -- "magnum reports
active / 'Unit is ready' regardless of whether it has run" -- with an
explicit instruction that this re-run/re-assertion applies even when this
whole Stage 7 pass is itself a redo after an earlier Stage 4-6 rebuild.

**COS deployment mechanism explicitly NOT invented:** D-105 rules only the
SCOPE (per-DC, in-scope, no Office1 roll-up); no decision in this repo
specifies whether COS means the `cos-lite` k8s bundle or machine-charm-
native observability. The runbook presents both real options with their
tradeoffs and defers the choice to the operator at execution time, logged
as a real architectural decision rather than picked for them.

**DC-parameterization notes are traced, not assumed:** confirmed by
reading which phase-06/07/08 scripts actually source `scripts/lib-net.sh`
(`phase-06-k8s-bootstrap.sh`, `phase-06-kubeconfig-gate.sh`, both via
`KEYSTONE_VIP_DEFAULT`) and require `lib_net_select_dc "$DC"` first, versus
which literals those runbooks already resolve dynamically per-run and need
no further changes.

VERIFIED: `bash scripts/repo-lint.sh` 0 fail, 1 documented legacy warn (no
fixes needed). NOT YET EXECUTED.

REVERT: `rm runbooks/dc-dc-phase6-designate-cos-magnum.md && git checkout
HEAD~ -- docs/dc-dc-deployment-workflow.md` (safe).

## Next actionable step

This is the last of the seven Stage 1-7 runbooks (tooling gap register
item #9 now CLOSED for authoring). Remaining work is the adversarial
review pass across everything built this session and the final
consolidation of the workflow doc, gap register, companion Artifact,
changelogs, and session ledger.