jakman85andClaude Opus 5
44983095e1
Every platform-health alert rule carries `runbook_url: "https://${BASE_DOMAIN}/runbooks/<name>"` — 42 annotations over 34 distinct names, across platform/monitoring/alerts.yaml, platform/monitoring/pvc-capacity-alerts.yaml, platform/cnpg/alerts.yaml and platform/kubevirt/alerts.yaml. There was no runbooks/ directory and no HTTPRoute serving that path: an in-cluster probe of https://home.keithjackson.dev/runbooks/node-down returned HTTP 404. Every alert that reached a human handed them a dead link at the exact moment the documentation is read, and the annotation made it look solved — the same green-surface-over-absent-mechanism class as the import Job that reported success while storing placeholder secrets. No alerts.yaml is touched and no runbook_url value changes. The existing URL scheme is made to resolve instead. WHAT LANDS - runbooks/<34>.md — one per name, each grounded in this cluster's real topology and, where one exists, its real incident history: the 2026-09-07 k3s-prod-1 etcd I/O starvation (measured PSI 11.36 vs 0.75/1.29, the exact journal lines, the four mechanisms proven inert), the Longhorn reboot tax and the freeze/thaw of concurrent-replica-rebuild-per-node-limit, Cilium's once-resolved egress interface cache (Ifindex 3 against a live 1780) and the absence of OSS failover, the CNPG 38-hour ContinuousArchiving=False with its measured 6.8 MiB/h disk-full clock and the 2026-09-12 aggregation-scope fix, the 2026-09-06 Keycloak lockout in which all 12 clients held literal placeholder secrets behind an entirely green cluster, the Velero R2 x-amz-tagging NotImplemented incompatibility and its v1.14.3-rc.2 pin, and swap re-enabling itself across reboots via systemd-gpt-auto-generator. Each page states what the alert means HERE, the first diagnostic commands, likely causes ordered by probability with a remediation each, and when to escalate or stop. - Every page uses FULLY-QUALIFIED resource names and says why: three CRDs register the kind `Backup` here, the bare short name resolves to Longhorn's (zero objects), so `kubectl get backup -A` prints "No resources found" on a cluster holding 6 Velero and 27 CNPG backups. Acting on that false negative is how a CLI quirk becomes data loss. - Every page states that kubectl only works via `infra/devcontainer/dev.sh run bash -c '...'` with an explicit `--context k3s-prod`, because dev.sh defaults its current-context to k3s-dev. - Pages also record which alert groups are INERT today (measured 2026-09-13: no Longhorn, cert-manager, Flux-controller or Hubble scrape job exists, so 13 rules evaluate against nothing) so nobody reads their silence as health. SERVING — runbooks/serving/ plus clusters/base/runbooks.yaml A two-replica nginx-unprivileged serving a ConfigMap generated from runbooks/*.md, at the apex `/runbooks` prefix, in its own non-gating post-platform Flux tier (dependsOn platform-config, wait:false) — the platform/homepage pattern, file for file. - The service catalog cannot express this route: ingressRoutes[].host is pattern-bound to a single DNS label plus the apex, so the bare apex is unrepresentable, and there is no path field. - Rejected: redirecting to the Gitea web UI. A runbook is read when the platform is broken, and Gitea is an app-tier workload whose own dependencies several of these runbooks document; Gateway API's RequestRedirect also has no "append .md" modifier, so it would need 34 hand-maintained ReplaceFullPath rules. - configMapGenerator maps each file to an EXTENSIONLESS key (node-down=node-down.md), so /runbooks/node-down is a plain static lookup with no rewrite rule. Served as text/plain: the namespace has DNS-only egress, so a CDN markdown renderer could not load anyway. - The tier declares NO postBuild.substituteFrom, deliberately: envsubst would run over the prose and silently empty every ${...} shell example (it fails open — the 2026-09-01 emptied Cilium k8sServiceHost). The HTTPRoute omits `hostnames:` and inherits the https-apex listener's, so nothing needs substituting. AUTH — PUBLIC, deliberately auth-mode=none. Gating these pages behind oauth2-proxy/Keycloak would make runbooks/keycloak-down unreadable when Keycloak is down and runbooks/keycloak-client-secrets unreadable during the exact 2026-09-06 failure mode. An operator who cannot log in is this route's primary reader. Content is operational procedure only, no secrets. The rationale is recorded in an annotation on the HTTPRoute so the route is left OUT of the Gateway ext-authz attachment when forward-auth enforcement lands. PROVEN — in-cluster probe through the Gateway on prod /runbooks/node-down HTTP 200 8613 bytes text/plain; charset=utf-8 /runbooks/keycloak-down HTTP 200 9378 bytes text/plain; charset=utf-8 /runbooks/cnpg-archiving HTTP 200 11729 bytes text/plain; charset=utf-8 /runbooks/longhorn-faulted HTTP 200 9135 bytes text/plain; charset=utf-8 /runbooks/vpn-down HTTP 200 11092 bytes text/plain; charset=utf-8 /runbooks/backup-failure HTTP 200 9604 bytes text/plain; charset=utf-8 HTTPRoute Accepted by io.cilium/gateway-controller on sectionName https-apex; the `/runbooks` prefix wins over homepage's apex `/` by Gateway API longest-path precedence. GUARD — conformance/tests/l0-static/alert-runbooks-resolvable (R-OBS-04) 363 offline assertions. It checks BOTH halves, because the regression is silent in both directions: an alert with a new runbook_url and no runbook links to a 404, AND a runbook committed without its configMapGenerator entry is in git, reviewed, merged, and still 404s in the cluster. Also asserts a quality floor so a stub cannot make the link look fixed, and that route/listener/nginx prefix agree with the annotations. Proven to fail, then reverted: a bogus runbook_url (2 FAIL), a runbook removed from the generator (1 FAIL), and a 31-byte stub (7 FAIL). Co-Authored-By: Claude Opus 5 <[email protected]>
120 lines
6.8 KiB
Markdown
120 lines
6.8 KiB
Markdown
# node-memory — Memory pressure high on a node
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**Alert:** `NodeMemoryPressureHigh` (warning, 10m)
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**File:** `platform/monitoring/alerts.yaml`, group `platform-health.nodes`
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**Expression:** `(1 - (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes)) > 0.90`
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## What this means here
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Available memory has been under 10% for ten minutes. These are HP EliteDesk 800 G5 Minis with
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~22 GiB usable, running the whole platform plus KubeVirt VMs on three nodes, so the headroom is
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genuinely thin and this alert is a capacity signal rather than a bug signal most of the time.
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Two cluster-specific facts change how you read it:
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**`SwapTotal == 0` is not evidence swap is off.** On 2026-09-07 all three prod nodes came back from a
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reboot with **977 MiB of swap ACTIVE** (`/dev/sda4` on prod-1 and prod-3, `/dev/nvme0n1p4` on prod-2)
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while the Ansible role's commented-out fstab line reported success.
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`systemd-gpt-auto-generator` claims any GPT partition typed
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`0657fd6d-a4ab-43c4-84e5-0933c84b4f4f` straight from the partition table and synthesises a `.swap`
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unit into `/run/systemd/generator.late/` — it never reads `/etc/fstab`. The fix masks `swap.target`
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(the single choke point for gpt-auto, fstab-generator and cryptsetup-generator). If a node is
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swapping, the kubelet's memory accounting is lying to you and eviction will misbehave. Check
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explicitly with `swapon --show`, never `SwapTotal`.
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**There is a kernel memory-reporting bug on all three nodes.** `infra/PROD-PROVISIONING.md` §0b
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records an EFI memattr defect that once presented `k3s-prod-1` as having **2.6 GiB usable of 16 GB**.
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It needs kernel ≥ 6.13 and all three nodes are exposed (prod-3 publishes `MEMATTR=0xbeece018` too).
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If `MemTotal` looks absurd rather than merely tight, suspect this before suspecting a leak.
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## Running the commands in this runbook
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`kubectl` does not work on the operator workstation. The toolchain lives only in the pinned dev
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container, and the host's `k3s-oidc` context hangs on a browser prompt once its token expires —
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that hang is not the cluster being down. Every command below runs as:
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infra/devcontainer/dev.sh run bash -c 'kubectl --context k3s-prod get nodes'
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Always pass `--context k3s-prod` explicitly. `dev.sh` merges both clusters into one kubeconfig and
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defaults its current-context to k3s-**dev**, so a command without `--context` silently answers
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about the wrong cluster. (`CLUSTER=prod infra/devcontainer/dev.sh run kubectl ...` is equivalent.)
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Do not run two `dev.sh` invocations at once — they share one container and interfere.
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USE FULLY-QUALIFIED RESOURCE NAMES, ALWAYS. Three CRDs on this cluster register the kind `Backup`:
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`longhorn.io/v1beta2`, `postgresql.cnpg.io/v1` and `velero.io/v1`. The bare short name resolves to
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Longhorn's, which holds zero objects — so `kubectl get backup -A` prints **"No resources found"** on
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a cluster holding 6 Velero backups and 27 CNPG backups. Verified on prod 2026-09-13. Reading that as
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"the backups are gone" and acting on it turns a false negative into real data loss. Write
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`backups.velero.io`, `backups.postgresql.cnpg.io`, `clusters.postgresql.cnpg.io`,
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`settings.longhorn.io`, `volumes.longhorn.io`, `nodes.longhorn.io`.
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Mutating kubectl (`apply`, `patch`, `annotate`, `rollout`) and `flux reconcile` are blocked for
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agents here: every durable change goes through git (`git push origin main` **is** the deploy).
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Where this runbook gives a mutating command it is for an operator, and it says so.
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## First commands
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```
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infra/devcontainer/dev.sh run bash -c \
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'kubectl --context k3s-prod top nodes; echo; kubectl --context k3s-prod get nodes -o custom-columns=NAME:.metadata.name,MEM:.status.capacity.memory,PRESSURE:.status.conditions[?\(@.type==\"MemoryPressure\"\)].status'
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```
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Who is using it — and is swap actually off?
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```
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ssh k3s-prod-1 'free -h; echo; swapon --show; echo "(empty output above = swap really off)"; echo; cat /proc/pressure/memory; echo; ps -eo pid,rss,comm --sort=-rss | head -15'
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```
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Biggest consumers in the cluster, and anything that has been OOM-killed:
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```
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infra/devcontainer/dev.sh run bash -c \
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'kubectl --context k3s-prod top pods -A --sort-by=memory | head -20; echo; \
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kubectl --context k3s-prod get events -A --field-selector reason=OOMKilling --sort-by=.lastTimestamp | tail -20'
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```
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## Likely causes, most likely first
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### 1. A monitoring component grew past its limit
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This is the one with real history. When kube-prometheus-stack went 65 → 88 it shipped Grafana 13 and
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**Grafana OOM-looped** — "the hidden blocker that stalled the whole kps upgrade and the platform
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tier". Limits went 256 → 512 → **768Mi** for Grafana and Prometheus 2 → **3Gi** (commit `b2b1aa5`).
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Prod keeps 30d retention / 45GiB retentionSize on a 50Gi PVC, so Prometheus is legitimately the
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largest single consumer. Remediation: raise the limit in
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`platform/monitoring/kube-prometheus-stack.yaml` and push; do not restart it in a loop.
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### 2. A KubeVirt VM, especially a TCG-emulated one
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VMs are the largest discretionary consumer. `useEmulation: false` is set deliberately (on v1.9
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`true` silently forces TCG), but leaked test namespaces running emulated VMs have caused API blips
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before and were deleted. Check `kubectl --context k3s-prod get vmi -A` and the `virt-launcher-*` pods'
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memory.
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### 3. Swap silently back on after a reboot
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See above. Verify with `swapon --show` and `systemctl is-enabled swap.target` (should be `masked`).
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`node_health` now reports `memory.swap_persistence` for this. The fix is the Ansible role; an
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operator runs it.
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### 4. Genuine capacity exhaustion
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If nothing is anomalous, the node is simply full. The node vCPU count was already raised 6 → 8 for
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CPU pressure; memory is next. A bpg/OpenTofu memory change **reboots the VM**, so roll **one node at
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a time and wait for Longhorn `robustness=healthy` between each** — the same discipline as every other
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reboot here.
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### 5. A leak in an app-tier workload
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Nextcloud, Plex and the *arr stack are the usual suspects. Compare `top pods` against the previous
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day in Grafana rather than guessing.
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## When to escalate or stop
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- **Escalate immediately if this is firing together with `node-io` or `node-down`** on the same node.
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Memory pressure plus I/O pressure on an etcd member is the shape of the 2026-09-07 outage.
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- **Do not add swap** to relieve this. Kubernetes does not want it here and the platform has already
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been bitten by swap re-enabling itself.
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- **Do not evict or drain** to free memory: this cluster does not drain (Longhorn rebuild cost). Kill
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the specific offending pod instead, and only if you know what it is.
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- Hand to the operator for anything requiring a VM resize or an Ansible run.
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---
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Source of truth: `runbooks/node-memory.md`. Index: `/runbooks/`
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Records: `DECISIONS-LOG.md` (Grafana OOM, kps 65→88); commits `0e92d25`/`9d00a3f` (swap persistence);
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`infra/PROD-PROVISIONING.md` §0b (EFI memattr).
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