home-network-k3s-impl/runbooks/backup-failure.md

backup-failure — A Velero backup failed

Alert: VeleroBackupFailure (critical, 5m) File: platform/monitoring/alerts.yaml, group platform-health.backups Expression: increase(velero_backup_failure_total[1h]) > 0

What this means here

A Velero backup in the last hour ended in phase=Failed. Off-cluster DR (R-STATE-03) is at risk. Velero backs up the cluster's Kubernetes objects and its Longhorn PVC data; it does not provide the DR path for the three CloudNativePG databases — CNPG owns those via its own Barman archive, because a Velero snapshot of a live Postgres is not a backup. So a Velero failure and a CNPG failure are separate incidents with separate runbooks (/runbooks/cnpg-archiving).

READ THIS BEFORE YOU CONCLUDE THE BACKUPS ARE GONE

kubectl get backup -A prints "No resources found" on this cluster even when backups exist. Three CRDs register the kind Backup — longhorn.io/v1beta2, postgresql.cnpg.io/v1 and velero.io/v1 — and the bare short name resolves to Longhorn's, which holds zero objects. Verified on prod 2026-09-13, where the fully-qualified queries returned 6 Velero backups and 27 CNPG backups while the short name returned nothing.

This has already caused two false "the backups are missing" conclusions in one night. A destructive recovery action taken on that false negative is how a monitoring quirk becomes real data loss. Use:

backups.velero.io           backups.postgresql.cnpg.io           backups.longhorn.io
schedules.velero.io         scheduledbackups.postgresql.cnpg.io  clusters.postgresql.cnpg.io

Where the backups go

Cloudflare R2, since the operator's 2026-09-05 decision (commit 32d6766). Prod cannot reach the on-Proxmox MinIO at all — measured from a prod pod, connection timed out after 15s — and that MinIO ran on the same physical host as dev's VMs, so dev's "off-cluster" backup shared a failure domain. Live config: endpoint https://7ce452a1b3d6c86daf2c020edcb82d37.r2.cloudflarestorage.com, region auto, bucket k3s-prod-backup, prefix velero, schedule 0 3 * * *, retention 720h. backupstoragelocation.velero.io/default should read Available.

Running the commands in this runbook

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. Every command below runs as:

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

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

USE FULLY-QUALIFIED RESOURCE NAMES, ALWAYS. Three CRDs on this cluster register the kind Backup: longhorn.io/v1beta2, postgresql.cnpg.io/v1 and velero.io/v1. The bare short name resolves to Longhorn's, which holds zero objects — so kubectl get backup -A prints "No resources found" on a cluster holding 6 Velero backups and 27 CNPG backups. Verified on prod 2026-09-13. Reading that as "the backups are gone" and acting on it turns a false negative into real data loss. Write backups.velero.io, backups.postgresql.cnpg.io, clusters.postgresql.cnpg.io, settings.longhorn.io, volumes.longhorn.io, nodes.longhorn.io.

Mutating kubectl (apply, patch, annotate, rollout) and flux reconcile are blocked for agents here: every durable change goes through git. main is a protected branch — a direct push is rejected. A change lands by pushing a branch, opening a PR, and merging it once the gate is green; that merge is the deploy. Where this runbook gives a mutating command it is for an operator, and it says so.

First commands

Which backup failed, and why — fully-qualified, always:

infra/devcontainer/dev.sh run bash -c \
  'kubectl --context k3s-prod get backups.velero.io -A \
     -o custom-columns=NAME:.metadata.name,PHASE:.status.phase,START:.status.startTimestamp,ERRORS:.status.errors,WARN:.status.warnings'

infra/devcontainer/dev.sh run bash -c \
  'kubectl --context k3s-prod -n velero get backups.velero.io <name> -o yaml | sed -n "/status:/,\$p"'

The storage location and the controller's log (the R2 error text is in the log, not the CR):

infra/devcontainer/dev.sh run bash -c \
  'kubectl --context k3s-prod -n velero get backupstoragelocations.velero.io,schedules.velero.io; echo; \
   kubectl --context k3s-prod -n velero logs deploy/velero --tail=150 2>&1 | grep -iE "error|NotImplemented|InvalidArgument|tagging|checksum" | tail -25'

Did the volume data upload even though the backup failed? (This distinction is the whole point — see cause 1.)

infra/devcontainer/dev.sh run bash -c \
  'kubectl --context k3s-prod -n velero get podvolumebackups.velero.io \
     -o custom-columns=NAME:.metadata.name,BACKUP:.metadata.labels.velero\\.io/backup-name,PHASE:.status.phase,BYTES:.status.progress.bytesDone'

The plugin pin (cause 1 depends entirely on this):

grep -n "velero-plugin-for-aws\|checksumAlgorithm\|region" platform/velero/helmrelease.yaml

Likely causes, most likely first

1. The R2 object-tagging incompatibility (the known, specific, repo-documented one)

velero-plugin-for-aws v1.14.2 sets PutObject's Tagging unconditionally — Tagging: aws.String(o.tagging) with o.tagging == "" — so the SDK emits x-amz-tagging: (empty) on every PutObject. R2 does not implement object tagging at all and answers:

NotImplemented: Header 'x-amz-tagging' with value '' not implemented

Observed live on prod twice, on the write of velero/backups/<name>/velero-backup.json. The shape of the failure is the dangerous part: kopia uploads the volume DATA successfully (its own S3 client), then the Backup goes phase=Failed with NO metadata object — an unrestorable backup. No configuration avoids it (config.tagging with a real value sends a tag set R2 also rejects). The fix is upstream PR #309, which landed on release-1.14 after v1.14.2 was cut, so the image is pinned to velero/velero-plugin-for-aws:v1.14.3-rc.2. EXIT CONDITION: move to v1.14.3 the moment it ships GA. Do NOT "clean this up" back to v1.14.2 — that silently breaks every prod backup's metadata. If this alert fires and the pin has drifted, that is your answer.

Two more mandatory R2 settings in the same file: config.checksumAlgorithm: "" (R2 rejects the AWS SDK's x-amz-checksum-* headers with HTTP 400 InvalidArgument — harmless against MinIO, fatal against R2) and region exactly auto (it was once hardcoded us-east-1, correct-by-accident for MinIO).

2. A placeholder or wrong endpoint

clusters/prod deliberately carried the loud placeholder https://TBD-R2-ACCOUNT-ID.r2.cloudflarestorage.com rather than inheriting the base (dev) value, because "an omitted op means prod silently inherits a dev address — far worse than a failed apply". Check S3_BACKUP_ENDPOINT, S3_BACKUP_REGION, VELERO_BACKUP_BUCKET, VELERO_BACKUP_PREFIX and BACKUP_CREDENTIALS_SUFFIX in clusters/base/cluster-vars.yaml and the prod overlay. A backupstoragelocation that is not Available points straight here.

3. Credentials

The R2 token lives in a SOPS-encrypted Secret (velero-cloud-prod.sops.yaml), and the velero tier carries its own decryption stanza. An expired or mis-scoped token gives 403s in the log.

4. A volume could not be read

Check podvolumebackups.velero.io for a specific volume. Note that NFS-sourced volumes are deliberately skipped by the velero-volume-policies ConfigMap — see /runbooks/backup-partial, which is where that belongs.

5. The node or storage was unhealthy during the run

Velero's daily runs at 03:00 and reads Longhorn PVCs. If a node was under I/O pressure or a volume was degraded, the read can fail. Cross-read /runbooks/node-io and /runbooks/longhorn-degraded.

When to escalate or stop

• Escalate promptly. This is a critical because it is a DR alarm: the cluster may currently have no recent restorable backup.
• Do not delete a Failed backup to "clean up". A Failed Velero backup can leave orphaned kopia blobs in the bucket — prod has two such backups from 2026-09-12 (prod-proof-20260912, prod-vp-probe-20260912) whose orphaned blobs are pending owner consent to delete. Deleting objects in R2 is an operator decision, not a tidy-up.
• Do not assume a Completed backup is restorable if the plugin pin has drifted — the failure mode is precisely "data uploaded, metadata missing".
• Be honest about restore: dr-restore is authored and has never been executed (conformance.home.k3s/never-executed), so the R2 restore path is unrehearsed. R2 egress is free, which is the whole reason restore rehearsals are affordable — but nobody has done one yet.
• The three CNPG databases are not covered by Velero. If the concern is a database, go to /runbooks/cnpg-archiving.

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Source of truth: runbooks/backup-failure.md. Index: /runbooks/ Records: commit 2e259a8 and platform/velero/helmrelease.yaml lines ~68-95 (the R2 tagging incompatibility, checksumAlgorithm, region: auto); commit 32d6766 (the move to R2); commit 2d5171e (Velero shipped with no ServiceMonitor, so these alerts could never fire).