jakman85andClaude Opus 4.8
6bc4406dca
Root cause of a W5 wedge: default 5m Helm timeout on slow-HDD Longhorn upgrades caused a rollback attempt after the data had already migrated to the new minor, which the old manager fatally refuses. Give the upgrade room and never auto-rollback (fail forward). Co-Authored-By: Claude Opus 4.8 <[email protected]>
99 lines
5.3 KiB
YAML
99 lines
5.3 KiB
YAML
---
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# Longhorn — distributed replicated block storage across the 3 nodes (ADR-0003).
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# Serves R-STATE-01 (state survives destroy/rebuild) and R-STATE-02 (3-way replication).
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#
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# Dev-appropriate values. Environment differences enter ONLY via ${...} substitution from
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# cluster-vars (R-ENV-02); everything else is identical base config for dev and prod.
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apiVersion: helm.toolkit.fluxcd.io/v2
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kind: HelmRelease
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metadata:
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name: longhorn
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namespace: longhorn-system
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spec:
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interval: 30m
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# Longhorn upgrades roll every workload + engine image on slow HDD-backed nodes and can exceed the
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# 5m Helm default; a short timeout caused a W5 mid-upgrade wedge (data migrated to the new minor but
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# workloads rolled back, and the new-version data refuses the old-version manager). Give it room.
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timeout: 15m0s
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chart:
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spec:
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chart: longhorn
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version: ">=1.12.0 <1.13.0" # W5 upgrade 1.11->1.12 (resolves 1.12.1; supports k8s 1.36). Renovate maintains
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sourceRef:
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kind: HelmRepository
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name: longhorn
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namespace: longhorn-system
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install:
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createNamespace: false # namespace.yaml owns it (GitOps-managed, labelled)
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remediation:
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retries: 3
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upgrade:
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remediation:
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retries: 3
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# NEVER auto-rollback a Longhorn minor upgrade: once the on-disk data migrates to the new minor,
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# the older manager fatally refuses it ("downgrading from vX to vY is not supported"). Rolling
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# back the workloads while data is already migrated wedges the cluster. Fail forward instead.
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remediateLastFailure: false
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values:
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# We own the StorageClasses (storageclasses.yaml) so the default 3-replica class and the bulk
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# tier are explicit and GitOps-managed. Disable the chart's built-in default SC so there is
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# exactly one default-class annotation in the cluster.
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persistence:
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defaultClass: false
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defaultSettings:
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# --- data path (R-STATE-02) ---
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# Dedicated Longhorn data disk (/dev/vdb → ext4) is mounted here by cloud-init on every node
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# (infra/cloud-init/user-data.yaml.tftpl). Longhorn stores replicas on this disk only.
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defaultDataPath: "/var/lib/longhorn"
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# --- replication (R-STATE-02) ---
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# Global fallback replica count. The `longhorn` StorageClass sets numberOfReplicas explicitly
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# (authoritative); this keeps any volume created without an explicit count consistent.
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# Substituted from cluster-vars.longhorn_default_replica_count (=3 in dev).
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defaultReplicaCount: ${LONGHORN_DEFAULT_REPLICA_COUNT}
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# --- replica anti-affinity across nodes (R-STATE-02 durability guarantee) ---
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# HARD anti-affinity: never place two replicas of the same volume on the same node, so a
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# single node loss cannot take down more than one replica. On a 3-node / 3-replica cluster
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# this yields exactly one replica per node.
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replicaSoftAntiAffinity: false
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# Single zone (3 mini-PCs, no failure zones): allow replicas within the one zone.
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replicaZoneSoftAntiAffinity: true
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# When a downed node returns, rebalance replicas back toward one-per-node (best-effort so it
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# never blocks scheduling).
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replicaAutoBalance: "best-effort"
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# --- rebuild I/O throttle for slow disks (etcd WAL fsync protection) ---
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# The k3s VM disks sit on HDDs, so a full-replica rebuild's sequential I/O can saturate the
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# spindle and starve etcd's WAL fsync — which crash-loops etcd and flaps the kube-vip VIP.
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# Cap Longhorn to rebuilding ONE replica per node at a time so a node bounce / replica
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# replenishment can never storm the HDDs. Deliberately conservative for this slow-disk cluster
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# (Longhorn's chart default is higher). Pair with replica-replenishment-wait-interval=600
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# (Longhorn default) so brief node bounces don't trigger replenishment at all.
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concurrentReplicaRebuildPerNodeLimit: 1
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# --- capacity guardrails (docs/04 "reserve disk headroom") ---
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# Reserve 20% of the dedicated data disk so a node never fills to 100% (which wedges the
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# kubelet and Longhorn alike). Dev disks are small, so headroom matters.
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storageReservedPercentageForDefaultDisk: "20"
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# Stop scheduling new replicas onto a disk once free space drops below 25%.
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storageMinimalAvailablePercentage: "25"
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# Dev: 200% thin over-provisioning — config-only volumes use little actual space, so the small
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# 39Gi data disks host the full app catalog. Physical fill risk is low (watch monitoring PVCs).
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# Prod-grade alternative: grow the Longhorn data disks and return to 1:1 (WS-STORAGE).
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storageOverProvisioningPercentage: "200"
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# --- misc dev-appropriate defaults ---
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# Keep replicas spread for durability rather than co-locating with the pod.
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defaultDataLocality: "disabled"
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# Reclaim replica space of deleted/failed volumes promptly in dev.
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orphanAutoDeletion: true
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# Longhorn's own manager/UI stay in-cluster; UI exposure (if any) is gated behind
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# oauth2-proxy forward-auth (ADR-0014) by WS-SEC — not exposed here.
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# TODO(WS-STORAGE, Phase 4): off-cluster backup target (defaultSettings.backupTarget +
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# backupTargetCredentialSecret) is configured alongside Velero (ADR-0003, R-STATE-03).
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# Credentials referenced BY NAME only, SOPS-encrypted (WS-SEC) — never inline here.
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