home-network-k3s-impl/runbooks

Alert runbooks — home-network-k3s prod

This is the index page served at https://home.keithjackson.dev/runbooks/.

Every alert rule in this platform carries an annotation of the form

runbook_url: "https://${BASE_DOMAIN}/runbooks/<name>"

46 of them, over the 35 names below. Until this directory existed, that path returned HTTP 404 on the live cluster: every alert that reached a human handed them a dead link at the exact moment they needed help. These pages are what makes the link resolve.

How to run the commands in these runbooks

kubectl does not work on the operator workstation. The toolchain lives only in the pinned dev container, and the host's k3s-oidc context hangs on a browser prompt once its token expires — that hang is not the cluster being down.

infra/devcontainer/dev.sh run bash -c 'kubectl --context k3s-prod get nodes'

Always pass --context k3s-prod. dev.sh merges BOTH clusters into one kubeconfig and picks a current-context per invocation, and that default has already changed once — k3s-dev until dev was decommissioned on 2026-09-13, k3s-prod now. A command that names its context still means the same thing next month; one that relies on the default does not, and the failure is silent. CLUSTER=prod infra/devcontainer/dev.sh run kubectl ... selects it explicitly, and every invocation prints a banner naming the cluster — read it. Do not run two dev.sh invocations at once; they share one container.

Use fully-qualified resource names, always. Three CRDs on this cluster register the kind Backup — longhorn.io/v1beta2, postgresql.cnpg.io/v1, velero.io/v1 — and the bare short name resolves to Longhorn's, which holds zero objects. kubectl get backup -A therefore prints "No resources found" on a cluster holding 6 Velero and 27 CNPG backups (verified on prod 2026-09-13). Acting on that false negative is how a CLI quirk becomes real data loss. Write backups.velero.io, backups.postgresql.cnpg.io, clusters.postgresql.cnpg.io, settings.longhorn.io, volumes.longhorn.io, nodes.longhorn.io.

git push origin main is the deploy; there is no other apply step. Durable changes go through git.

Alerts you should not trust the silence of (measured 2026-09-13)

Prometheus scrapes 19 jobs on prod. There is no Longhorn, cert-manager, Flux-controller or Hubble/Cilium job, so these rule groups currently evaluate against nothing and cannot fire:

Missing scrape job	Inert alerts
Longhorn	LonghornVolumeDegraded, LonghornVolumeFaulted, LonghornVolumeCapacityHigh, LonghornNodeStorageHigh
cert-manager	CertificateExpiringSoon, CertificateExpiryImminent, CertificateNotReady
Flux (gotk_*)	FluxReconciliationFailure, FluxResourceSuspended, ImageUpdateAutomationFailing, ImagePolicyStalled, UpdateHealthGateFailed
Hubble (hubble_drop_total)	HubbleDeniedFlowSpike
etcd (kubeEtcd disabled for k3s, deliberately)	no etcd fsync alerting exists at all

Each affected runbook says so on its own page and gives the by-hand equivalent. See targets-down.

The runbooks

Nodes

• node-down — a node's node-exporter is unscrapable; the node may be gone, or its kubelet may have stopped posting status while the host stays up (the 2026-09-07 shape).
• node-io — disk I/O pressure/starvation. The etcd WAL shares a partition with Longhorn replicas; this is the alert that would have called the 2026-09-07 outage and did not exist at the time.
• node-memory — memory pressure. Includes why SwapTotal == 0 is not evidence swap is off.
• node-disk — a node filesystem filling up. /data is the one that matters.
• node-cpu — CPU PSI and run-queue depth, and how to tell CPU contention from I/O contention.

Storage

• longhorn-degraded — a volume has lost redundancy. Normal after any reboot, and the rebuild is the expensive part. Freeze/thaw commands here.
• longhorn-faulted — no usable replica. Data at risk; stop before anything destructive.
• longhorn-capacity — a volume or a node's Longhorn disk near capacity.
• pvc-capacity — PVC filling up / almost full / predicted to fill. These rules work.
• monitoring-capacity — Prometheus or Loki running out of disk; don't let the monitor blind itself.

GitOps and updates

• flux-reconcile — a Flux resource stuck at Ready=False. Which tier decides the blast radius.
• flux-suspended — reconciliation turned off and forgotten. Drift becomes silent.
• update-rollback — a HelmRelease failed its health gate and is rolling back.
• image-automation — the git write-back engine is failing (feature is disabled here).
• image-policy-stalled — an ImagePolicy/ImageRepository cannot resolve a tag.

Certificates

• cert-issuance — ACME issuance failing. The DNS-01 self-check is the usual cause.
• cert-expiry — a certificate is expiring. Almost always a late symptom of cert-issuance.

Networking

• vpn-down — the egress VPN tunnel. Includes the silent egress-gateway staleness that this alert cannot see, and what the kill-switch actually does.
• denied-flows — policy-denied flow spike. The Cilium hairpin/identity regression class.

Backups and DR

• backup-failure — a Velero backup failed. The R2 object-tagging incompatibility is documented here.
• backup-partial — a Velero backup completed with partial failures, and which skips are deliberate.
• backup-missed — no successful Velero backup in 24h.
• cnpg-archiving — WAL archiving stuck / no recoverability point. An availability incident, not just a backup one.
• cnpg-backup-missed — no recent CNPG base backup. Velero does not cover these databases.
• cnpg-wal-growth — pg_wal not being recycled. Never delete WAL by hand.
• cnpg-exporter — the CNPG SQL exporter erroring: a blind spot that looks exactly like health.
• cnpg-primary-spread — two or more CNPG primaries on one node. Blast radius, not an outage, and the rebalance costs ~9s of writes per database — one cluster at a time.

Identity

• keycloak-down — the IdP is down. Blast radius, and the break-glass path that still works.
• keycloak-db — Keycloak's CloudNativePG database is unavailable.
• keycloak-client-secrets — the client/URL reconciler failing or silent. The 2026-09-06 lockout that every green signal missed.

Virtualisation

• kubevirt-control-plane — VM lifecycle operations will fail; running VMs keep running.
• kubevirt-launch-failed — a VMI reached the Failed phase. The three k3s-specific launch traps.
• kubevirt-crashloop — a virt-launcher pod restarting repeatedly.
• cdi-import-stuck — a DataVolume import not progressing. Check node I/O before restarting it.

Editing a runbook

Each page is runbooks/<name>.md in the home-network-k3s-impl repo. Edit it, push to main, and Flux re-renders the ConfigMap and rolls the two-replica server; kustomize's content hash on the generated ConfigMap name is what triggers the roll.

Adding a new alert with a runbook_url requires the matching runbooks/<name>.md and its <name>=<name>.md entry in runbooks/kustomization.yaml. Both are enforced by conformance/tests/l0-static/alert-runbooks-resolvable, which runs unconditionally in the merge gate — "the file exists in git" and "the URL resolves in the cluster" are different claims, and it checks both.

Every page must carry the four operator sections (What this means here, First commands, Likely causes, most likely first, When to escalate or stop), mention dev.sh, and pass --context k3s-prod. The check enforces that too, because a stub that makes the link resolve while helping nobody is worse than the 404 it replaced — it looks fixed.

Why this route has no login

Deliberately public. Every other exposed UI here declares forward-auth via oauth2-proxy → Keycloak; if these pages did too, keycloak-down would be unreadable exactly when Keycloak is down, keycloak-db unreadable when its database is down, and keycloak-client-secrets unreadable during the precise failure that broke all 12 OIDC clients on 2026-09-06 behind an entirely green cluster. An operator who cannot log in is this route's primary reader. The content is operational procedure — metric names, thresholds, kubectl invocations, topology — and no secrets. See runbooks/serving/httproute.yaml for the full reasoning, including the instruction to leave this route out of the Gateway ext-authz attachment when forward-auth enforcement lands.

The running narrative of real incidents on this cluster is DECISIONS-LOG.md.