0.5.0: Longhorn local snapshots + async S3 backup (#347 phase 5)

Chart.yaml

@@ -23,8 +23,8 @@ description: |
       Git).
 
 type: application
-version: 0.4.0
-appVersion: "0.4.0"
+version: 0.5.0
+appVersion: "0.5.0"
 
 dependencies:
   - name: cert-manager

templates/longhorn-recurringjobs.yaml

@@ -0,0 +1,57 @@
+{{- /*
+Phase 5 of ADR 0003 — two-layer protection for tenant volumes.
+
+Layer A — local CoW snapshots (`task: snapshot`)
+  Hourly. Instant. Zero blocking. Block-level CoW means the snapshot
+  shares blocks with live data; only diverged writes consume new
+  space. Cheap to keep ~24 hours of granular undo.
+
+Layer B — async S3 backup (`task: backup`)
+  Daily. Block-incremental. The customer's workflow never waits on
+  the upload — Longhorn streams blocks to the configured S3 target
+  in the background. Renders the cluster's data durable off-cluster
+  even if Layer A snapshots are wiped (e.g. server reformat).
+
+Both layers are independent of Tower's existing application-level
+pg_dump backup. The application backup captures higher-level
+semantic state (schema-aware, restorable to a different PG major
+or cluster) and is what makes cross-cluster migration possible.
+The Longhorn layers capture block-level state and are what makes
+fast same-cluster restore possible. Both run; the customer keeps
+both. Decision 0002 (Standard tier ships always-on durable backup)
+is satisfied by the application layer alone; Longhorn-S3 is the
+velocity-and-redundancy upgrade.
+
+Both jobs target Longhorn's `default` group, which auto-includes
+every volume with no explicit recurring-job reference. So the
+schedule applies to existing AND future tenant PVCs without
+operator action per-instance.
+*/ -}}
+{{- if .Values.longhorn.enabled }}
+---
+apiVersion: longhorn.io/v1beta2
+kind: RecurringJob
+metadata:
+  name: tenants-snapshot-hourly
+  namespace: longhorn-system
+spec:
+  cron: "0 * * * *"
+  task: snapshot
+  groups: [default]
+  retain: 24
+  concurrency: 2
+{{- if .Values.longhorn.defaultSettings.backupTarget }}
+---
+apiVersion: longhorn.io/v1beta2
+kind: RecurringJob
+metadata:
+  name: tenants-backup-daily
+  namespace: longhorn-system
+spec:
+  cron: "0 3 * * *"
+  task: backup
+  groups: [default]
+  retain: 7
+  concurrency: 2
+{{- end }}
+{{- end }}

values.yaml

@@ -144,23 +144,36 @@ csiSnapshotter:
 longhorn:
   enabled: false
   # Replicas per Longhorn volume. Standard tier (single server) =
-  # 1 — durability story is hourly S3 backup, not local replicas.
+  # 1 — durability story is async S3 backup, not local replicas.
   # HA-Active sets this to 2 across the cluster's worker nodes.
   replicas: 1
-  # Default data path. k3s nodes get `/var/lib/longhorn` by default;
-  # production servers may want this on a separate disk for IOPS
-  # isolation from the OS root volume.
-  defaultDataPath: /var/lib/longhorn
-  # S3 backup target for Longhorn's own block-level backups (DR
-  # layer alongside Tower's application-level pg_dump path). When
-  # set, Longhorn writes block-incremental backups to this prefix
-  # daily. Empty = block-level backup disabled, application backup
-  # only.
-  backupTarget: ""
-  # Same S3 secret Tower's application backup already uses.
-  backupCredsSecret:
-    namespace: tenants
-    name: s3-backup-creds
+  # Phase 5 of ADR 0003 — Longhorn's own settings, passed straight
+  # through to the subchart's `defaultSettings`. The two-layer design:
+  #
+  #   1. Local CoW snapshots (Longhorn `task: snapshot`) — instant,
+  #      zero-blocking, hourly retention. Used for fast undo.
+  #   2. Async S3 backup (Longhorn `task: backup`) — block-incremental
+  #      upload to tenant's bucket, gradual, never blocks workflow.
+  #      Daily retention. The DR layer alongside Tower's existing
+  #      application-level pg_dump backup (which is for cross-cluster
+  #      migration; Longhorn-S3 is for fast same-cluster restore).
+  #
+  # The RecurringJob CRDs that drive both layers live in
+  # templates/longhorn-recurringjobs.yaml and bind to all volumes
+  # via the `default` group automatically.
+  defaultSettings:
+    defaultDataPath: /var/lib/longhorn
+    # backupTarget — set this per-server via the Argo App's helm
+    # parameters to enable the async S3 backup channel. Format:
+    # `s3://<bucket>@<region>/<prefix>/`. Empty = local snapshots
+    # only (local layer still works; just no off-cluster copy).
+    backupTarget: ""
+    # backupTargetCredentialSecret — name of K8s Secret in the
+    # `longhorn-system` namespace carrying AWS_ACCESS_KEY_ID +
+    # AWS_SECRET_ACCESS_KEY. Operator kubectl-applies it once per
+    # cluster (same pattern as cloudflare-api-token). Cross-namespace
+    # Secret references aren't allowed by Longhorn.
+    backupTargetCredentialSecret: ""
   # Disable the Helm pre-upgrade checker Job. It's annotated as a
   # `helm.sh/hook: pre-upgrade,pre-install` which Argo translates to
   # PreSync — but the Job's ServiceAccount lives in the regular sync