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home-network-k3s-impl/apps/wave-0/nextcloud-db.yaml
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feat(cnpg): instances 3 on all three Clusters — a standby to fail over to
All three CNPG Clusters ran `instances: 1`. Longhorn's 3-way replication
saves the DATA when a node dies; it does not save the SERVICE — a single
instance has to be rescheduled, re-attach its volume and replay WAL before
Postgres accepts a connection again.

With nothing in the spec keeping them apart, all three primaries had drifted
onto ONE node (k3s-prod-2 on prod, k3s-dev-3 on dev). On 2026-09-07 that node
took SSO, Nextcloud and Semaphore down together, and with SSO went kubectl
OIDC, Grafana, Headlamp, Gitea and forward-auth.

Three instances give each Cluster a streaming standby CNPG can promote in
seconds, repointing the -rw Service with no volume re-attach and no restore.

UNBLOCKED BY WORKING BACKUPS, NOT A SUBSTITUTE FOR THEM. Standbys replicate
corruption and deletions faithfully; only the Barman archive is a backup, and
adding standbys while archive_mode=on with a failing archive_command would
have multiplied the disk-full clock, not hedged it. All three Clusters on
both k3s-prod and k3s-dev now report ContinuousArchiving=True with a real
firstRecoverabilityPoint (verified read-only, 2026-09-07).

Scaling out is non-disruptive on its own: CNPG creates -2 then -3
sequentially, each seeded by pg_basebackup from the RUNNING primary. The
primary is not restarted and clients are not disconnected. The anti-affinity
change that DOES cause a switchover is deliberately the next commit.

DEV IMPACT: identical — dev is on the same shape (three single-instance DBs,
all on k3s-dev-3) and gets the same scale-out. Dev has three untainted nodes
and Longhorn headroom for it (see the next commit's message for the numbers).

Cost: 2 extra 5Gi PVCs per Cluster; ~30 GiB provisioned cluster-wide against
live pgdata of ~600 MiB each, on Longhorn with 200% over-provisioning.

Verified: yamllint clean; `kubectl kustomize --load-restrictor
LoadRestrictionsNone platform-config` and `kubectl kustomize apps/wave-0`
both render `instances: 3`.

Co-Authored-By: Claude Opus 5 <[email protected]>
(cherry picked from commit ed6fe6cb019b96f677a92448a0347f979d1a6d02)
2026-09-07 23:41:31 -05:00

131 lines
6.7 KiB
YAML

---
# Nextcloud's PostgreSQL — a CloudNativePG Cluster (CR of the CNPG CRDs from platform/cnpg), modeled
# on platform/keycloak/postgres-cluster.yaml. This is the first CNPG-DB in apps/ and establishes the
# reusable pattern for later DB-backed services (semaphore, unifi, ...).
#
# WHY A DEDICATED `nextcloud-db` NAMESPACE (not co-located in `nextcloud`):
# The app->db edge in catalog/nextcloud.yaml (`dependencies: to: nextcloud-db`) compiles to a
# CiliumNetworkPolicy whose egress selector pins BOTH the destination pod label
# (app.kubernetes.io/name=nextcloud-db) AND its namespace (k8s:io.kubernetes.pod.namespace=
# nextcloud-db) — cross-namespace Cilium selectors must name the namespace (catalog/render.py
# r_dependency_policies). So the DB MUST live in a namespace literally named `nextcloud-db` and its
# pods MUST carry app.kubernetes.io/name=nextcloud-db, injected below via inheritedMetadata.
#
# DEFAULT-DENY POSTURE — mirrors keycloak (platform/keycloak/namespace.yaml): this namespace is
# INTENTIONALLY not homelab.keithjackson.dev/app-namespace=true, so Kyverno does NOT generate the app
# default-deny baseline here and CNPG runs under Cilium's cluster-wide default-allow — the SAME posture
# the verified keycloak-db uses. The nextcloud SIDE keeps its default-deny; its rendered egress-allow
# opens ONLY nextcloud -> nextcloud-db:5432, and the DB side's default-allow accepts that reciprocal
# ingress. No app-namespace policy (auth-mode/host-namespace/secret-provenance) is weakened.
apiVersion: v1
kind: Namespace
metadata:
name: nextcloud-db
labels:
# Match the Cilium egress selector's namespace pin; NOT an app-namespace (see header).
app.kubernetes.io/name: nextcloud-db
---
# Owner credentials for the CNPG cluster. SOPS-encrypted (age); type basic-auth so CNPG's initdb
# consumes it as the `nextcloud` role's password instead of generating a random one — this lets the
# SAME password be mirrored into ns nextcloud (nextcloud-bootstrap/db-password) for the app's env,
# since a Pod cannot read a Secret in another namespace. Provided as apps/nextcloud-db-app.sops.yaml.
#
# CNPG Cluster (CR of postgresql.cnpg.io installed by platform/cnpg).
apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
name: nextcloud-db
namespace: nextcloud-db
spec:
# THREE instances — one primary + two hot standbys (2026-09-07), same as keycloak-db; see
# platform/keycloak/postgres-cluster.yaml for the full rationale. Short version: Longhorn's 3-way
# replication saves the DATA on node loss, not the SERVICE, and with `instances: 1` all three CNPG
# primaries had drifted onto k3s-prod-2, so one node took Nextcloud down alongside SSO and
# Semaphore. A streaming standby lets CNPG promote in seconds and repoint the -rw Service.
# Gated on the Barman archive below actually working (ContinuousArchiving=True with a real
# firstRecoverabilityPoint) — standbys replicate corruption, they are not a backup.
#
# Scaling out is non-disruptive: CNPG creates -2 then -3 sequentially, each seeded by
# pg_basebackup from the running primary, which is neither restarted nor disconnected.
instances: 3
imageName: ghcr.io/cloudnative-pg/postgresql:16.4
# Stamp app.kubernetes.io/name=nextcloud-db onto every generated pod/service so the rendered
# nextcloud egress CiliumNetworkPolicy's toEndpoints selector matches the primary pod (R-NET-02).
inheritedMetadata:
labels:
app.kubernetes.io/name: nextcloud-db
storage:
storageClass: longhorn
size: 5Gi
bootstrap:
initdb:
database: nextcloud
owner: nextcloud
# Use the pre-provisioned owner secret (basic-auth) so its password is known + reusable by the
# app in the other namespace, instead of the random CNPG-generated one.
secret:
name: nextcloud-db-app
# Emit Postgres metrics so Prometheus scrapes DB health (R-OBS-01). The CNPG operator creates the
# PodMonitor at runtime (CRD present from Phase-4 monitoring).
monitoring:
enablePodMonitor: true
resources:
requests:
cpu: 100m
memory: 256Mi
limits:
memory: 512Mi
# --- Off-cluster DR backup (R-STATE-03) — CNPG-native Barman → object storage ---
# Continuous WAL archiving + periodic base backups = proper Postgres PITR (realises the SD's
# backup.policy daily-offcluster). CNPG appends serverName (defaults to the Cluster name) to
# destinationPath, so objects land under ${CNPG_BACKUP_PATH}/nextcloud-db/ — dev
# s3://cnpg/nextcloud-db/ on the on-Proxmox MinIO, prod
# s3://k3s-prod-backup/barman/nextcloud-db/ on Cloudflare R2. Both endpointURL and
# destinationPath are cluster-vars knobs (R-ENV-02), substituted by `apps-wave-0`.
# Credentials: PER-ENVIRONMENT (2026-09-07). dev reads nextcloud-db-backup-credentials (the
# scoped MinIO key), prod reads nextcloud-db-backup-credentials-prod (the Cloudflare R2
# token). BOTH Secrets are applied to BOTH clusters by apps/wave-0/kustomization.yaml (a
# generated golden — render.py places the -prod sidecar in this DB's wave); the
# cluster-vars knob ${BACKUP_CREDENTIALS_SUFFIX} (dev "" | prod "-prod") chooses which
# one this Cluster reads. Both are in-namespace, which is all a pod can read. They were
# ONE shared Secret until the split, so giving prod its R2 token would have left dev
# signing MinIO requests with an R2 key id — 403 on every archive command, i.e. the
# disk-full clock below rather than a merely missing backup.
#
# archive_mode is ON, so a FAILING archive command is a disk-full clock, not a degraded backup:
# Postgres refuses to recycle a WAL segment it has not archived, and the pgdata PVC fills until
# the primary PANICs. Prod demonstrated this from bootstrap to 2026-09-07 with a placeholder
# endpoint. Treat ContinuousArchiving=False here as an availability incident.
backup:
retentionPolicy: "30d"
barmanObjectStore:
destinationPath: ${CNPG_BACKUP_PATH}
endpointURL: ${S3_BACKUP_ENDPOINT}
s3Credentials:
accessKeyId:
name: nextcloud-db-backup-credentials${BACKUP_CREDENTIALS_SUFFIX}
key: ACCESS_KEY_ID
secretAccessKey:
name: nextcloud-db-backup-credentials${BACKUP_CREDENTIALS_SUFFIX}
key: ACCESS_SECRET_KEY
wal:
compression: gzip
maxParallel: 2
data:
compression: gzip
---
# Daily base backup of nextcloud-db (WAL archived continuously by the barmanObjectStore above). CNPG
# cron is 6-field (sec min hour dom mon dow); immediate:true seeds the first base backup. 02:00 slot.
apiVersion: postgresql.cnpg.io/v1
kind: ScheduledBackup
metadata:
name: nextcloud-db-daily
namespace: nextcloud-db
spec:
immediate: true
schedule: "0 0 2 * * *"
backupOwnerReference: self
cluster:
name: nextcloud-db
method: barmanObjectStore