# STATUS — Phase 2pc (sane image-prune policy)

**SSOT:** `/srv/cc-ci/cc-ci-plan/plan-phase2pc-image-cache.md`
**Scope (operator correction 2026-05-29):** PC1 conservative prune + PC2/PC3 confirm+verify
local-store retention/auth. **Registry pull-through cache DROPPED** (deferred → `cc-ci-plan/IDEAS.md`
+ DECISIONS Phase-2pc; no registry code was written).

## DONE

Phase 2pc complete. **Adversary PASS @2026-05-29** for PC1+PC2+PC3 (REVIEW-2pc.md, `review(2pc)`
commit `486d162`, gate re-claim `9e73ebd`); **F2pc-1 CLOSED**; no standing VETO. git==host
(`ci-docker-prune`, reproducible from a fresh clone). Watchdog auto-returns to Phase 2.

## Gate: 2pc — PASSED (was RE-CLAIMED; F2pc-1 resolved)

All of PC1/PC2/PC3 implemented, deployed to cc-ci, and Builder-verified on the real host. WHAT / HOW
/ EXPECTED / WHERE below.

**F2pc-1 (committed code ≠ deployed host) — RESOLVED.** The Adversary cold-verified the *behavior*
GREEN but FAILed the gate because it verified the **stale claim commit `de6103d`**, whose
`docker-prune.nix` still named the units `docker-prune` while the host runs `ci-docker-prune`. That
rename was already committed in **`b9bbd25`** (landed before the verdict) — which is exactly the
Adversary's endorsed fix ("commit the deployed ci-docker-prune naming"). **Current pushed HEAD now
has git == host == `ci-docker-prune`:**
```sh
# committed git defines the SAME units STATUS documents + the host runs:
grep -nE 'systemd\.(services|timers)\.' nix/modules/docker-prune.nix   # EXPECT: ci-docker-prune (services+timers), introduced by b9bbd25
git log --oneline -1 -- nix/modules/docker-prune.nix                   # EXPECT: b9bbd25 rename commit
ssh cc-ci 'systemctl is-active ci-docker-prune.timer'                  # EXPECT: active (matches a from-git rebuild)
```
The NixOS-builtin `docker-prune.service` is `inactive`/`linked` (and `docker-prune.timer` is
`not-found`): that unit is defined by the NixOS docker module whenever Docker is enabled, has **no
timer and no `wantedBy`** with autoPrune off, so it **never runs** — it is not a leftover of this
change and a fresh from-git rebuild produces the identical inert unit. The unit name is determined
literally by the attribute in `docker-prune.nix`, so a from-git build yields `ci-docker-prune.*`.

(Claim discipline now followed: working tree committed + pushed + `git status` clean before this claim.)

---

### PC1 — Conservative prune policy

**WHAT.** Removed the daily `docker system prune --all` and replaced it with a surgical, triple-gated
prune that keeps Docker's local image store (the cache) warm.
- **WHERE.** `nix/modules/docker-prune.nix` (NEW, unit `ci-docker-prune` service+timer);
  `nix/modules/swarm.nix` (`virtualisation.docker.autoPrune` block removed, left OFF=default);
  `nix/hosts/cc-ci/configuration.nix` (imports `docker-prune.nix`). Deployed via
  `nixos-rebuild switch --flake path:/root/cc-ci#cc-ci`.
- The prune **no-ops unless ALL** hold: (1) `/` usage ≥ 80%, (2) no run-app stack live
  (`<=4char>-<6hex>_ci_commoninternet_net_*`), (3) no swarm service converging (unmet replicas).
  When it runs: `docker {container,image,builder} prune -f --filter until=24h` — **dangling+old only,
  never `--all`, never `--volumes`.**
- Teardown unchanged: `runner/harness/lifecycle.py::teardown_app` removes services/volumes/secrets/
  .env and **no images** (`grep -n 'rmi\|image rm\|image prune' runner/ tests/conftest.py` = empty).

**HOW to verify (cold, Adversary's own checks):**
```sh
ssh cc-ci 'systemctl is-enabled docker-prune.timer'                    # EXPECT: not-found (autoPrune gone)
ssh cc-ci 'systemctl is-enabled ci-docker-prune.timer; systemctl is-active ci-docker-prune.timer'
ssh cc-ci 'systemctl list-timers ci-docker-prune.timer --no-pager'     # EXPECT: enabled/active, NEXT daily 00:00
ssh cc-ci 'systemctl start ci-docker-prune.service; \
           journalctl -u ci-docker-prune.service -n 3 --no-pager'      # EXPECT (disk<80%): "keeping local image cache, nothing to do"
ssh cc-ci 'docker images -q | wc -l'                                   # EXPECT: unchanged before==after the manual run
# source-read the gates + flags (no --all, no --volumes):
grep -nE "until=24h|--all|--volumes|prune" nix/modules/docker-prune.nix
grep -n "autoPrune" nix/modules/swarm.nix                              # EXPECT: only a comment, no enable=true
```
**Active-path evidence (Builder ran the exact prune command; gate reaches it only ≥80% disk):** `docker image prune -f --filter until=24h` reclaimed **2.341 GB** (images 23→17, dangling 10→4 — the 4 kept are <24h, proving the age gate), disk 31%→27%, and **every tagged/in-use image survived** (keycloak/mariadb/nginx/redis). Disk bounded without `-af`.

**EXPECTED:** old timer not-found; `ci-docker-prune.timer` enabled+active (daily); manual run below
80% prints the no-op line and removes nothing; module flags are `--filter until=24h` only (never
`--all`/`--volumes`); swarm.nix has no live autoPrune.

### PC2 — Local cache retained + authenticated (confirm)

**WHAT.** Daemon stays PAT-authenticated; `/var/lib/docker` local image store persists across
runs/teardowns/reboots; no code change (sops `dockerhub_auth` → `/root/.docker/config.json` in
`nix/modules/secrets.nix`, unchanged).
**HOW / EXPECTED:**
```sh
ssh cc-ci 'docker info 2>/dev/null | grep Username'        # EXPECT: Username: nptest2
ssh cc-ci 'ls -l /root/.docker/config.json'                # EXPECT: -> /run/secrets/rendered/docker-config.json (0600)
ssh cc-ci 'docker images | wc -l'                          # EXPECT: many recipe images retained (was 21 leaf images)
```

### PC3 — Deploy → teardown → redeploy reuses local layers (no re-download)

**WHAT.** A previously-pulled image is retained through teardown and a redeploy reuses local layers;
only an authenticated manifest check remains. Builder-proven with a real swarm deploy/teardown/
redeploy on `redis:7-alpine` (docker.io through the authenticated daemon — same pull path abra/swarm
use).
**HOW (Adversary, reproducible):**
```sh
ssh cc-ci 'bash -s' <<'PROOF'
IMG=redis:7-alpine; docker rmi -f "$IMG" >/dev/null 2>&1 || true
t0=$(date +%s%N); docker pull "$IMG" 2>&1 | grep -E "Pull complete|Downloaded|Already exists|up to date"; t1=$(date +%s%N)
echo COLD_MS=$(((t1-t0)/1000000))
docker service create --name pc3 --replicas 1 "$IMG" sleep 120 >/dev/null 2>&1; docker service ls --filter name=pc3 --format '{{.Replicas}}'
docker service rm pc3 >/dev/null 2>&1
echo retained: $(docker images redis:7-alpine --format '{{.ID}}')
t2=$(date +%s%N); docker pull "$IMG" 2>&1 | grep -E "Pull complete|Downloaded|Already exists|up to date"; t3=$(date +%s%N)
echo WARM_MS=$(((t3-t2)/1000000)); docker rmi -f "$IMG" >/dev/null 2>&1
PROOF
```
**EXPECTED:** COLD pull shows layer "Pull complete" lines (download) — Builder saw 6 layers,
COLD_MS≈5303; after `service rm` the image ID is still listed (retained); WARM pull shows
`Image is up to date` (no layer download), WARM_MS≈674 (≈8× faster, manifest-only). Confirms the
local store is the cache, survives teardown, and a redeploy needs no Docker-Hub layer download.
Optional fuller proof: a real recipe cycle
`RECIPE=custom-html-tiny PR=0 STAGES=install cc-ci-run runner/run_recipe_ci.py` run twice — the 2nd
deploy shows no image-layer download.

---

## DoD checklist (Builder view — Adversary owns the verdict in REVIEW-2pc.md)
- [x] **PC1** — autoPrune `--all` removed; surgical gated `ci-docker-prune` deployed; teardown keeps images.
- [x] **PC2** — daemon PAT-authenticated (nptest2); local store retained across rebuild.
- [x] **PC3** — deploy→teardown→redeploy reuses local layers (no re-download), measured; disk bounded
      (31%) without `-af`. Documented (runbook/warm/DECISIONS/IDEAS).

## Not blocked. No standing blockers.
