feat(upgrades): automated OS reboots (kured) + security-only unattended-upgrades, and give Renovate a runner

Two halves of one repeatable upgrade process. Neither works alone.

(a) OS upgrades and reboots

platform/kured/ — Kubernetes Reboot Daemon, chart 6.1.0/app 1.23.0, in its own
Flux Kustomization (dependsOn platform, wait:true). NOT in platform/kustomization.yaml:
that tier gates platform-config and every apps wave, so a wedged reboot daemon there
could stall every application. A component added to make maintenance safer must not be
able to cause an outage.

infra/ansible/roles/unattended_upgrades/ — new role (node_baseline is touched by other
open branches, and this is a different lifecycle), enabled for prod in group_vars.

The human gate is the SENTINEL, which is how this honours node_baseline's "IT DOES NOT
REBOOT" (k3s-prod-2 hung on a warm reboot 2026-09-03) and cluster-upgrade-plan.md's
rejection of automating away the gate between nodes: u-u is security-only with the
kernel blacklisted, so it essentially never writes /var/run/reboot-required. That file
appears when an operator deliberately runs node-baseline.yml --tags kernel. kured then
does only the mechanical half, including the ordering rule node_baseline has to shout.

Quorum: concurrent reboots are structurally impossible, not merely unlikely.
concurrency:1 plus kured's single lock annotation (API-server optimistic concurrency),
and lockTtl:0 — an expiring lock is exactly the 3-node etcd catastrophe, so a hung node
holds it forever and nothing cascades.

Longhorn: measured 25 volumes x 3 replicas, hard anti-affinity, 600s replenishment wait,
serialized rebuild — so every drain degrades ALL volumes to 2/3 and the inter-node gate
must be volume robustness, not pod readiness. Doubled: lockReleaseDelay 30m
(unconditional) plus kured's Prometheus alert gate (semantic).

alertFilterMatchOnly:true is load-bearing — the flag inverts the regexp's meaning, and
under the chart default kured would have been blocked on day one by the five alerts
measured firing with no end in sight, and never rebooted anything.

Kernel floor (kernel >= 6.13, EFI memattr): excluded TWICE. The running kernel comes
from o=Debian Backports, which is not an allowed origin, so u-u cannot see a kernel
upgrade; and ^linux- is blacklisted anyway so widening origins later cannot re-arm it.
Asserted against apt-config dump, not against the file just written. 6.12 kernels are
still installed and bootable on all three nodes, and nothing was held.

Closes a silent no-op: update-notifier-common was absent on all three nodes, so NOTHING
could create the sentinel. kured alone would have idled forever at 1/1 Running.

platform/kured/alerts.yaml — three rules over kured's only metric, with a companion
promtool suite pinning each both ways, plus runbooks/node-reboot-automation.md.
Window is DAILY 03:00-06:00 because a weekly one forces for:8d, longer than this
cluster's 7d Prometheus retention.

(b) Image/dependency automation

Renovate was aspirational: renovate.json present and complete, with no workflow, no
in-cluster workload, and its docker+kubernetes managers disabled — so every plain
image: tag was maintained by nothing while seven files claimed otherwise.

.gitea/workflows/renovate.yaml — scheduled daily, dry_run default true for a safe
first run, and a preflight that FAILS (not skips) without RENOVATE_TOKEN, because a
skipped Gitea job reports success and that is how this stayed inert.

Renovate now owns both halves; Flux image-automation is formally closed: it pushes
commits rather than opening PRs (bypassing CLAUDE.md §1), and it cannot work here
anyway — main is protected user_can_push:false and the flux-system GitRepository has
no secretRef. Its controllers are installed and have idled 43 days with zero CRs.

conformance/: +34/-0, one new SCRAPE_OWNERS entry claiming kured_. Weakens nothing;
tightens the check for this component (requires service.create+metrics.create, both
chart-default false, plus a companion NetworkPolicy requirement). Required because
assertion (3) fails an alert over an unclaimed metric and KNOWN_UNWIRED_METRICS is
shrink-only.

Sensitive paths touched: clusters/**, conformance/**, .gitea/** — needs a non-author
approving review; /approve-override deliberately NOT posted.

NOT verified: no OS upgrade run, no node rebooted, no lock observed, the Ansible role
never executed, and whether CNPG switches its primary on a drain-induced eviction (the
most likely way the first real reboot fails). Full list in the handoff entry.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

decisions/2026-10-17-automated-upgrades.md

@@ -0,0 +1,251 @@
+---
+date: 2026-10-17
+branch: feat/automated-upgrades
+title: Automated upgrades — kured + security-only unattended-upgrades, and Renovate finally gets a runner
+---
+
+## What changed
+
+Two halves of one process. Neither is useful alone and they must land together.
+
+### (a) OS upgrades and reboots
+
+**`platform/kured/`** — the Kubernetes Reboot Daemon, chart `6.1.0` / app `1.23.0`, in its own Flux
+Kustomization (`clusters/base/kured.yaml`, `dependsOn: [platform]`, `wait: true`), registered in
+`clusters/base/kustomization.yaml`. Not a line in `platform/kustomization.yaml`: that tier is
+`wait: true` and gates `platform-config` → every apps wave, so a wedged reboot daemon placed there
+could stall every application in the cluster. A component added to make maintenance safer must not
+be able to cause an outage.
+
+**`infra/ansible/roles/unattended_upgrades/`** + `playbooks/unattended-upgrades.yml`, enabled for
+prod in `inventory/group_vars/k3s_prod/vars.yml`. A **new** role rather than an extension of
+`node_baseline` — different lifecycle, and other open branches touch that role.
+
+**The design, and how it answers this repo's two standing objections to reboot automation.**
+`roles/node_baseline/tasks/main.yml:61-67` says "IT DOES NOT REBOOT" (k3s-prod-2 hung on a warm
+reboot 2026-09-03; physical power button required), and `docs/plans/cluster-upgrade-plan.md:291-299`
+rejected system-upgrade-controller for "automating away the human gate between nodes". Both still
+stand. **The human gate is the sentinel.** unattended-upgrades is security-only with the kernel
+blacklisted, so it essentially never produces `/var/run/reboot-required`; that file appears when an
+operator deliberately runs `node-baseline.yml --tags kernel`. kured then performs only the
+*mechanical* half the operator would otherwise type by hand — including the ordering rule
+`node_baseline`'s own output has to shout ("NEVER node 2 first"), which the operator keeps by
+running the kernel play with `--limit <host>` one node at a time. `cluster-upgrade-plan.md:329-330`
+names the condition under which its own rejection reverses (fast disks), and prod is that cluster.
+
+**Quorum: concurrent reboots are structurally impossible.** All three nodes are control-plane+etcd
+(quorum 2/3). `concurrency: 1` plus kured's single cluster-wide lock annotation on its own DaemonSet
+means a node reboots only while holding that lock, enforced by API-server optimistic concurrency
+rather than by timing. **`lockTtl: 0`** (expiry disabled) is the deliberate choice: a TTL exists so
+reboots continue after the lock holder dies, which on 3 etcd nodes is exactly the catastrophe — a
+hung node's lock expiring would let a second node take the cluster to 1/3. So a hang stops the cycle
+forever and pages a human. `lockReleaseDelay: 30m` holds the lock after a node returns.
+
+**The Longhorn gate.** Measured: 25 volumes, all `numberOfReplicas: 3`, one replica per node, with
+`replica-soft-anti-affinity: false` and `disable-scheduling-on-cordoned-node: true`. So every drain
+takes **all 25 volumes to degraded 2/3**, and recovery is serialized —
+`replica-replenishment-wait-interval: 600`, `concurrent-replica-rebuild-per-node-limit: 1`. Reboot
+the next node too early and volumes reach 1/3, where `node-drain-policy:
+block-if-contains-last-replica` can block a drain forever. The inter-node gate is therefore **volume
+robustness, not pod readiness**, and it is doubled: `lockReleaseDelay: 30m` (unconditional, covers
+the 600s wait) plus kured's Prometheus alert gate (semantic, covers a rebuild longer than 30m).
+
+**`alertFilterMatchOnly: true` is load-bearing.** The flag inverts the regexp's meaning: `false`
+(chart default) makes it an *ignore* list and kured blocks on **any** firing alert. Measured
+2026-10-17, five alerts were firing with no end in sight (`CNPGPrimariesCoLocated`,
+`KubeDeploymentReplicasMismatch`, `KubeDeploymentRolloutStuck`, `KubePodNotReady`,
+`OAuth2ProxyGateUnobserved` — the last three all tracing to `pm-agent`, ImagePullBackOff on a
+placeholder digest for 12 days). Under the default, kured would have been blocked on day one and
+never rebooted anything, indistinguishable from "no reboots needed". The allow-list is anchored:
+`^(LonghornVolumeDegraded|LonghornVolumeFaulted|KubeNodeNotReady|NodeExporterDown)$`.
+`NodeEtcdRequestsSlow` and the `NodeIOPressure*` family are **deliberately excluded** despite being
+exactly what you'd want to pause for — prod-1 has a documented etcd WAL I/O starvation history and
+including them risks a permanent wedge that looks like safety.
+
+**The kernel floor (the highest-risk item), handled with two independent exclusions.** Measured: all
+three nodes run `7.1.8+deb13-amd64` (`7.1.8-1~bpo13+1`, the backports metapackage), far above the
+6.13 memattr floor — **but `linux-image-6.12.107` and `linux-image-6.12.94` are also still
+installed, below the floor, bootable, and `apt-mark showhold` is empty on every node.** So: (1) the
+allowed-origins list is `label=Debian-Security` only, and the running kernel comes from
+`o=Debian Backports` (pin 100, the `NotAutomatic`+`ButAutomaticUpgrades` signature), so u-u cannot
+*see* a kernel upgrade; (2) `^linux-` is blacklisted anyway, so widening origins later — the most
+likely future edit — cannot re-arm the hazard. The role **asserts both against `apt-config dump`**,
+apt's own parse of the whole directory, rather than trusting the file it just wrote. Also blacklisted:
+`intel-microcode`, `amd64-microcode`, `grub-*`. `Remove-Unused-Kernel-Packages` is **false** against
+the Debian default, because those older kernels are the documented rollback path. None of this stops
+the kernel moving — the operator's deliberate Ansible run still does that, unchanged.
+
+**The silent-no-op trap this closes.** Measured: `update-notifier-common`, `needrestart` and
+`unattended-upgrades` were **absent on all three nodes**, so *nothing could create
+`/var/run/reboot-required`*. kured deployed alone would have been permanently idle while 1/1 Running
+and reporting `kured_reboot_required=0` — green forever. The role installs the sentinel writer and
+**asserts a hook exists** by discovery (not a hard-coded path), failing loudly if not.
+`needrestart` runs in auto mode with `k3s.service` blacklisted — auto-restart is what makes a
+security-only policy effective, but restarting the control plane unattended is worse than a delayed
+library fix. (k3s is not an apt package at all here: no `k3s`, no `containerd` in dpkg.)
+
+**Alerts + runbook.** `platform/kured/alerts.yaml` — three rules over kured's *only* metric
+(`kured_reboot_required`, one GaugeVec, read from `cmd/kured/main.go:92-96`) plus `kube_node_info`:
+`KuredNotReporting` (`absent()` — the pipeline is dead and the other two are inert),
+`KuredNodeCoverageGap` (`count(kured) < count(nodes)` — a node silently uncovered, which `absent()`
+cannot see), `KuredRebootPending` (`for: 36h` — a reboot was offered and blocked). Companion
+promtool suite `alerts.promtool-test.yaml` pins all three both ways, including that the rule
+**stops** when a reboot succeeds. `runbooks/node-reboot-automation.md` registered in
+`runbooks/kustomization.yaml`.
+
+**The window is DAILY 03:00-06:00, and that choice is driven by the alert.** A weekly window means a
+pending reboot legitimately waits 6 days, forcing `for: 8d`+ — longer than this cluster's 7d
+Prometheus retention and reset by any restart past the 1h for-outage-tolerance. Daily caps the
+legitimate wait under 24h and makes `for: 36h` both robust and meaningful.
+
+### (b) Image / dependency automation
+
+**Renovate was aspirational. It now has a runner.** `.gitea/workflows/renovate.yaml` — scheduled
+daily 03:15 UTC, `workflow_dispatch` with `dry_run` defaulting to **true** for a safe first run.
+Preflight **fails hard (exit 1)** if `RENOVATE_TOKEN` is missing rather than skipping, because a
+skipped Gitea job reports `success` and that is precisely how `renovate.json` stayed inert.
+
+**`renovate.json`: Renovate now owns both halves, and Flux image-automation is formally closed.**
+ADR-0009 gave container image tags to Flux image-automation; that cannot be delivered on this
+repo's terms. (1) `ImageUpdateAutomation` **pushes commits, it does not open PRs**, so it bypasses
+the CLAUDE.md §1 gate; pointed at a side branch instead, nothing opens the PR. (2) It cannot work
+here anyway: `main` is protected `user_can_push: false` and the `flux-system` GitRepository has **no
+`spec.secretRef`** — the source is anonymous and read-only. (3) Enabling it means an in-cluster git
+**write** credential for the repo that defines the cluster. So `docker`/`kubernetes` — disabled
+*only* to avoid fighting that controller — are enabled, with `kubernetes.managerFilePatterns`
+covering `platform/`, `platform-config/`, `apps/`, **`catalog/`** (apps are generated from it; a bump
+only to the rendered output is reverted by the next render and fails `ci/render-golden.sh`),
+`runbooks/serving/` and `infra/agent/`. Added a no-automerge `blast-radius` rule for `kured`,
+`longhorn`, `cilium`, `cloudnative-pg`, `kube-prometheus-stack`, because the gate is static and does
+not boot a node or form a quorum. `platform/kyverno/tests/**` added to `ignorePaths`.
+
+### Sensitive paths — this PR needs a non-author approving review
+
+It touches **`clusters/**`**, **`conformance/**`** and **`.gitea/**`**, all in
+`infra/gitea/approval-policy.json`. It will **not** merge on a green gate alone. Per CLAUDE.md §1 I
+have **not** posted `/approve-override` and must not — that is the self-approval the stage exists to
+prevent.
+
+**The `conformance/` edit, justified.** `+34/-0` in
+`alert-metrics-have-scrape-targets/check.sh`: one new `SCRAPE_OWNERS` entry claiming `kured_`. It
+**weakens nothing** — no existing owner's evaluation changes — and it *tightens* the check for my
+own component, adding two `require` patterns (`service.create: true`, `metrics.create: true`; the
+chart defaults **both** to false) plus a `companion` requirement that `networkpolicy.yaml` stay in
+the kustomization. It had to be touched: assertion (3) fails any alert over an unclaimed metric, and
+the escape hatch `KNOWN_UNWIRED_METRICS` is **shrink-only**, so declaring `kured_*` as debt was not
+permitted and would have been wrong anyway. The alternative was shipping reboot automation with no
+alerting, which for a component whose every failure mode is silent is the worse choice. The entry
+carries a dated comment saying all of this.
+
+## What I verified
+
+Measured against the live cluster and nodes, read-only, on 2026-10-17.
+
+- **Flux image-automation controllers ARE installed and idle.** `-n flux-system get deploy` shows
+  `image-automation-controller` and `image-reflector-controller` both `1/1`, age **43d**; all three
+  `image.toolkit.fluxcd.io` CRDs exist. And **zero** `ImageRepository`/`ImagePolicy`/
+  `ImageUpdateAutomation` objects — "No resources found" for each. The controllers have run for 43
+  days with nothing to do. `platform/kustomization.yaml:52` has the component commented out.
+- **Renovate is aspirational, confirmed three ways**: no workflow in `.gitea/` or `ci/` (grep),
+  no Renovate CronJob/Deployment/Job in any namespace, and `renovate.json` itself disabled the
+  `docker`+`kubernetes` managers — so every plain `image:` tag was maintained by **nothing**, while
+  **seven files** claim "Renovate maintains this pin".
+- **`flux-system` GitRepository has no `secretRef`** (empty), URL is the in-cluster Gitea, and its
+  artifact revision was `main@sha1:1a0b208…`, matching my base.
+- **Nodes**: 3× Debian 13 trixie, all `control-plane,etcd`, k3s `v1.36.4+k3s1`, kernel
+  `7.1.8+deb13-amd64`. `apt-mark showhold` **empty**; `/etc/apt/preferences.d/` **empty**;
+  `/var/run/reboot-required` absent; `unattended-upgrades`/`update-notifier-common`/`needrestart`
+  all **absent**; `linux-image-6.12.107` and `6.12.94` installed alongside the backports kernel;
+  no `k3s`/`containerd` apt package; `apt-cache policy` origins and pins as quoted above.
+- **No node taints** on any of the three (so no tolerations needed), and `system-node-critical`
+  exists.
+- **Longhorn**: 1.12.1; `node-drain-policy: block-if-contains-last-replica`;
+  `replica-soft-anti-affinity: false`; `disable-scheduling-on-cordoned-node: true`;
+  `replica-replenishment-wait-interval: 600`; `concurrent-replica-rebuild-per-node-limit: 1`;
+  25 volumes all 3-replica/healthy; 25 replicas per node.
+- **6 PDBs with 0 allowed disruptions**: 3× `longhorn-system/instance-manager-*` (structurally 0 —
+  single-node selector, `minAvailable: 1`) and 3× CNPG `*-primary`. All three Postgres primaries
+  were on `k3s-prod-1`.
+- **kured drain flags do not exist.** Read `cmd/kured/main.go:438-449`: `Force`,
+  `DeleteEmptyDirData` and `IgnoreAllDaemonSets` are **hardcoded true**. Passing
+  `--ignore-daemonsets`/`--delete-emptydir-data`/`--force` as extraArgs would CrashLoop the
+  DaemonSet. All three are genuinely needed (12 DaemonSets, 135 emptyDir pods measured).
+- **kured exposes exactly one metric** — the only `MustRegister` in the project.
+- **Prometheus selectors are all `{}`** (`serviceMonitorSelector`, `serviceMonitorNamespaceSelector`,
+  `ruleSelector`, `ruleNamespaceSelector`), so a `PrometheusRule`/`ServiceMonitor` in a new namespace
+  is picked up with no label plumbing.
+- **`count(kube_node_info) == 3`** and `count(longhorn_volume_robustness) == 100`, queried through a
+  read-only port-forward. The 5 chronically-firing alerts were read from `/api/v1/alerts`.
+- **`LonghornVolumeDegraded`** is `longhorn_volume_robustness{state="degraded"} == 1`, `for: 10m` —
+  shorter than Longhorn's own 600s replenishment wait, so degradation reliably outlasts the latch.
+- **kured chart 6.1.0 → appVersion 1.23.0** is the newest of 80 entries in the chart index.
+- **Kyverno/PSA will not block it**: every policy is scoped
+  `app-namespace: "true"`; the namespace sets it explicitly `"false"`, and
+  `restrict-host-namespaces.yaml`'s own header states that carve-out. No cluster-wide PSA baseline.
+- **`renovate.json` parses** as valid JSON after my edits (`json.load`).
+- **kured is not installed** and the string `kured` appears nowhere in the repo — greenfield.
+
+## What I did NOT verify
+
+The honest list. Most of this needs an actual upgrade cycle, which I did not and could not run.
+
+- **I never ran an OS upgrade, never rebooted a node, and never watched kured take a lock.** No part
+  of the runtime behaviour of either half has been observed. `sudo` needs a password I do not have,
+  so I could not run `apt`, `unattended-upgrade --dry-run`, or install anything. **Everything about
+  (a) working is inference from configuration and measured cluster state, not observation.**
+- **The Ansible role has never been executed.** Not syntax-checked by `ansible-playbook --syntax-check`
+  either (no inventory access from the gate). Its asserts, its `apt-config dump` parsing, and the
+  sentinel-hook discovery are all unproven. The `find` patterns for the sentinel hook are a *guess at
+  which package ships what* — I could not read `update-notifier-common`'s file list (packages.debian.org
+  returned no such package for that suite/arch), which is exactly why the role discovers rather than
+  hard-codes. **If no hook matches, the role fails loudly — but it may fail on a correct node.**
+- **Whether CNPG actually switches the primary in response to a drain-induced eviction.** All three
+  `*-primary` PDBs are structurally 0-disruption and `.spec.nodeMaintenanceWindow` is unset on all
+  three clusters. If the operator does not switch over, draining `k3s-prod-1` blocks on three PDBs at
+  once and hits `drainTimeout`. **This is the most likely way the first real reboot fails.** It
+  should be tested with one manual, watched `kubectl drain` before trusting the timer.
+- **Whether `drainTimeout: 15m` is long enough.** Unmeasured. The `unifi` VMI has
+  `evictionStrategy: LiveMigrate` with `migrationMethod: BlockMigration`, i.e. a full root-disk copy
+  over the network on every `k3s-prod-1` drain. I do not know how long that takes.
+- **Whether the alert gate actually blocks as intended.** I never saw kured query Prometheus. The
+  assumption that it treats a query error as "do not proceed" is from its documented behaviour, not
+  observed. The NetworkPolicy allowing kured→Prometheus:9090 and Prometheus→kured:8080 is
+  **unproven**; if either is wrong the symptom is silence, which is why `KuredNotReporting` exists —
+  but that alert is itself unproven against a live scrape.
+- **The alert expressions have not run against real `kured_*` data**, because the metric does not
+  exist in this cluster yet. They pass promtool unit tests against synthetic series whose shape I
+  read from kured's source. `absent()` and the `count() < count()` comparison are the two most
+  likely to behave differently against real label sets.
+- **`enabledManagers: ["regex"]` may be the wrong name.** Modern Renovate expects `custom.regex` for
+  `customManagers`. I left the pre-existing value alone rather than guess, but **the inline
+  `# renovate:` markers may simply not run.** Unverifiable without executing Renovate. Two markers
+  are additionally known-broken independent of this: `external-snapshotter`'s sits two comment lines
+  above its `newTag`, and Keycloak's `kustomization.yaml` has no marker at all despite a comment
+  claiming Renovate maintains it.
+- **Renovate has still never run.** I added the runner; `RENOVATE_TOKEN` does not exist yet, so the
+  first scheduled run **will fail** (by design). Nothing about the config is proven correct until a
+  `dry_run: true` dispatch is read by a human. Expect it to want to open ~30 PRs.
+- **No alert for "automatic patching silently stopped".** u-u's success lives in
+  `/var/log/unattended-upgrades/` on each node and nothing reads it. Likewise **no alert for the
+  Renovate schedule ceasing to fire**. Both are real gaps I did not close.
+- **`coredns` is 1 replica and I did not fix it.** It is k3s-managed, out of this PR's scope, and it
+  means every `k3s-prod-1` reboot causes a cluster-wide in-cluster DNS gap. Recommended follow-up.
+- **kured cannot honour "NEVER node 2 first".** It has no ordering control. The mitigation — run the
+  kernel play with `--limit` one host at a time — is a *procedure*, documented in the runbook, not an
+  enforced property. If the operator flags all three nodes at once, kured picks the order.
+- **kured cannot press a power button.** The 2026-09-03 warm-reboot hang is unmitigated. Bounded, not
+  prevented: quorum holds at 2/3, the lock is held forever so nothing cascades, and
+  `KuredRebootPending` eventually fires.
+- **Upstream version claims are a snapshot, partly from search results**, not all from authoritative
+  release APIs. I could not determine latest for versitygw, crafty, nginx-unprivileged, act_runner,
+  `virt-template-*`, the linuxserver wireguard date-tag, or the exact latest PostgreSQL 16 patch
+  (sources conflicted 16.10 vs 16.15). **The gitea `1.24.3 → v28.1.0` gap is almost certainly an
+  upstream versioning-scheme change, not 26 majors — do not act on that framing.**
+- **I did not verify Renovate's `kustomize` manager still processes `images:`/`newTag`** now that
+  `docker` is enabled, which decides whether `external-snapshotter` and `intel-gpu-plugin` are
+  managed at all.
+- **I did not raise any HelmRelease version ceiling**, so the 9 minor-locking ranges still cap
+  Renovate at patches. Bumping `kube-prometheus-stack` in particular will fail the gate until
+  `ci/versions.env`'s exact promtool/Prometheus `3.14.0` lockstep moves with it.
+- **L2/L3 conformance did not run** (`vars.CLUSTER_AVAILABLE` unset), so nothing here is proven
+  against a cluster by CI either.