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kured: drop Mon-Fri restriction, reboot any day

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The weekday-only schedule was a 2026-03-16-incident-era guardrail when
the rest of the safety net was thin. Today's gates — halt-on-alert,
sentinel-gate Check 4 (24h soak via node Ready transitions), the
K8sUpgradeStalled alert, drainTimeout=30m, concurrency=1, and the
sentinel-path fix from earlier today — make weekend reboots safe and
just clear the backlog faster.

Effect: 5 pending node reboots clear in 5 calendar days instead of
queueing up over weekends. The K8s version-upgrade detection at Sun
12:00 UTC self-defers if a Sunday-morning kured reboot fires (the
RecentNodeReboot alert is in the Upgrade Gates ignore-less list for
the version-upgrade preflight — same mechanism kured uses).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
Viktor Barzin 2026-05-16 12:29:01 +00:00
parent 8cbfa6856c
commit 48abb7c520
4 changed files with 17 additions and 8 deletions
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docs/architecture/automated-upgrades.md
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@ -218,7 +218,7 @@ Independent of the service-upgrade pipeline above. Drives apt package updates +
### Stack
- **In-guest**: `unattended-upgrades` runs apt upgrades within Allowed-Origins (`-security`, `-updates`, ESM). Package-Blacklist excludes runtime components (`containerd`, `containerd.io`, `runc`, `cri-tools`, `kubernetes-cni`, `calico-*`, `cni-plugins-*`, `docker-ce`). `apt-mark hold` on `kubelet`, `kubeadm`, `kubectl` (and runtime pkgs as belt-and-braces). `Automatic-Reboot=false` — kured handles reboots.
- **Reboot driver**: `kured` (chart `kured-5.11.0`, app `1.21.0`). Window Mon-Fri 02:00-06:00 Europe/London, period=1h, concurrency=1, reboot-delay=30s.
- **Reboot driver**: `kured` (chart `kured-5.11.0`, app `1.21.0`). Window 02:00-06:00 Europe/London every day of the week (Mon-Fri-only restriction dropped 2026-05-16 — see PM), period=1h, concurrency=1, reboot-delay=30s, drainTimeout=30m.
- **Reboot gate (sentinel)**: `kured-sentinel-gate` DaemonSet creates `/var/run/gated-reboot-required` only when (a) host needs reboot, (b) all nodes Ready, (c) all calico-node pods Running, (d) **no node has transitioned Ready in the last 24h** (24h soak window).
- **Reboot gate (Prometheus)**: kured `--prometheus-url` polls `prometheus-server.monitoring.svc:80` before each drain. ANY firing alert blocks unless it matches the ignore-regex `^(Watchdog|RebootRequired|KuredNodeWasNotDrained|InfoInhibitor)$`.
- **Health alert library**: 10 alerts in the `Upgrade Gates` group (`prometheus_chart_values.tpl`): `KubeAPIServerDown`, `KubeStateMetricsDown`, `PrometheusRuleEvaluationFailing`, `PVCStuckPending`, `RecentNodeReboot` (the explicit 24h soak signal), `MysqlStandaloneDown`, `ClusterPodReadyRatioDropped`, `NodeMemoryPressure`, `NodeDiskPressure`, `KubeQuotaAlmostFull`. Plus the existing 200+ alerts in the cluster-wide library (anything firing blocks kured).