feat(open-webui): HA deployment with CNPG, PDB, and session persistence

- Switch from SQLite/PVC to CNPG PostgreSQL (3 instances, low-resource)
  with a transaction-mode PgBouncer pooler (2 instances)
- Raise open-webui replicas to 3 with priorityClassName: power
- Add PodDisruptionBudget (minAvailable: 1)
- Add Gateway API sessionPersistence (cookie) on the HTTPS HTTPRoute
  so WebSocket connections stick to the same backend pod
- Add postgres-credentials VaultStaticSecret; DATABASE_URL must be
  added to kv/kubernetes/namespace/open-webui/default/open-webui-credentials

apps/base/open-webui/cnpg_cluster.yaml

@@ -0,0 +1,91 @@
+---
+apiVersion: postgresql.cnpg.io/v1
+kind: Cluster
+metadata:
+  name: open-webui-postgres
+  namespace: open-webui
+spec:
+  affinity:
+    podAntiAffinityType: preferred
+  bootstrap:
+    initdb:
+      database: open-webui
+      encoding: UTF8
+      localeCType: C
+      localeCollate: C
+      owner: open-webui
+      secret:
+        name: postgres-credentials
+  enablePDB: true
+  enableSuperuserAccess: false
+  failoverDelay: 0
+  imageName: ghcr.io/cloudnative-pg/postgresql:17-minimal-trixie
+  instances: 3
+  logLevel: info
+  maxSyncReplicas: 0
+  minSyncReplicas: 0
+  monitoring:
+    customQueriesConfigMap:
+      - key: queries
+        name: cnpg-default-monitoring
+    disableDefaultQueries: false
+    enablePodMonitor: false
+  postgresql:
+    parameters:
+      archive_mode: "on"
+      archive_timeout: 5min
+      dynamic_shared_memory_type: posix
+      effective_cache_size: 128MB
+      full_page_writes: "on"
+      log_destination: csvlog
+      log_directory: /controller/log
+      log_filename: postgres
+      log_rotation_age: "0"
+      log_rotation_size: "0"
+      log_truncate_on_rotation: "false"
+      logging_collector: "on"
+      max_connections: "100"
+      max_parallel_workers: "4"
+      max_replication_slots: "16"
+      max_worker_processes: "4"
+      shared_buffers: 64MB
+      shared_memory_type: mmap
+      ssl_max_protocol_version: TLSv1.3
+      ssl_min_protocol_version: TLSv1.3
+      wal_keep_size: 128MB
+      wal_level: logical
+      wal_log_hints: "on"
+      wal_receiver_timeout: 5s
+      wal_sender_timeout: 5s
+    syncReplicaElectionConstraint:
+      enabled: false
+  primaryUpdateMethod: restart
+  primaryUpdateStrategy: unsupervised
+  probes:
+    liveness:
+      isolationCheck:
+        connectionTimeout: 1000
+        enabled: true
+        requestTimeout: 1000
+  replicationSlots:
+    highAvailability:
+      enabled: true
+      slotPrefix: _cnpg_
+    synchronizeReplicas:
+      enabled: true
+    updateInterval: 30
+  resources:
+    limits:
+      cpu: 500m
+      memory: 512Mi
+    requests:
+      cpu: 100m
+      memory: 256Mi
+  smartShutdownTimeout: 180
+  startDelay: 3600
+  stopDelay: 1800
+  storage:
+    resizeInUseVolumes: true
+    size: 5Gi
+    storageClass: cephrbd-fast-delete
+  switchoverDelay: 3600

apps/base/open-webui/cnpg_pooler.yaml

@@ -0,0 +1,33 @@
+---
+apiVersion: postgresql.cnpg.io/v1
+kind: Pooler
+metadata:
+  name: open-webui-postgres-pooler
+  namespace: open-webui
+spec:
+  cluster:
+    name: open-webui-postgres
+  instances: 2
+  pgbouncer:
+    parameters:
+      default_pool_size: "50"
+      max_client_conn: "200"
+    paused: false
+    poolMode: transaction
+  template:
+    metadata:
+      labels:
+        app: pooler
+    spec:
+      affinity:
+        podAntiAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            - labelSelector:
+                matchExpressions:
+                  - key: app
+                    operator: In
+                    values:
+                      - pooler
+              topologyKey: kubernetes.io/hostname
+      containers: []
+  type: rw

apps/base/open-webui/deployment.yaml

@@ -0,0 +1,61 @@
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: open-webui
+  namespace: open-webui
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: open-webui
+  template:
+    metadata:
+      annotations:
+        reloader.stakater.com/auto: "true"
+      labels:
+        app: open-webui
+    spec:
+      priorityClassName: power
+      containers:
+        - name: open-webui
+          image: ghcr.io/open-webui/open-webui:main
+          imagePullPolicy: Always
+          ports:
+            - containerPort: 8080
+              name: http
+              protocol: TCP
+          env:
+            - name: OPENAI_API_BASE_URL
+              value: https://litellm.k8s.syd1.au.unkin.net
+            - name: WEBUI_URL
+              value: https://chat.k8s.syd1.au.unkin.net
+          envFrom:
+            - secretRef:
+                name: open-webui-credentials
+          livenessProbe:
+            httpGet:
+              path: /health
+              port: 8080
+            failureThreshold: 3
+            initialDelaySeconds: 30
+            periodSeconds: 30
+            successThreshold: 1
+            timeoutSeconds: 5
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: 8080
+            failureThreshold: 3
+            initialDelaySeconds: 10
+            periodSeconds: 10
+            successThreshold: 1
+            timeoutSeconds: 5
+          resources:
+            limits:
+              cpu: "2"
+              memory: 4Gi
+            requests:
+              cpu: 250m
+              memory: 512Mi
+      restartPolicy: Always

apps/base/open-webui/gateway.yaml

@@ -0,0 +1,37 @@
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  labels:
+    traefik.io/instance: internal
+  annotations:
+    cert-manager.io/cluster-issuer: vault-issuer
+    cert-manager.io/common-name: chat.k8s.syd1.au.unkin.net
+    cert-manager.io/private-key-size: "4096"
+    external-dns.alpha.kubernetes.io/hostname: chat.k8s.syd1.au.unkin.net
+    external-dns.alpha.kubernetes.io/target: 198.18.200.4
+  name: open-webui
+  namespace: open-webui
+spec:
+  gatewayClassName: traefik-internal
+  listeners:
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: chat.k8s.syd1.au.unkin.net
+      name: http
+      port: 80
+      protocol: HTTP
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      hostname: chat.k8s.syd1.au.unkin.net
+      name: https
+      port: 443
+      protocol: HTTPS
+      tls:
+        certificateRefs:
+          - group: ""
+            kind: Secret
+            name: open-webui-tls
+        mode: Terminate

apps/base/open-webui/httproute.yaml

@@ -0,0 +1,53 @@
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: open-webui-http-redirect
+  namespace: open-webui
+spec:
+  hostnames:
+    - chat.k8s.syd1.au.unkin.net
+  parentRefs:
+    - group: gateway.networking.k8s.io
+      kind: Gateway
+      name: open-webui
+      sectionName: http
+  rules:
+    - filters:
+        - type: RequestRedirect
+          requestRedirect:
+            scheme: https
+            statusCode: 301
+      matches:
+        - path:
+            type: PathPrefix
+            value: /
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: open-webui
+  namespace: open-webui
+spec:
+  hostnames:
+    - chat.k8s.syd1.au.unkin.net
+  parentRefs:
+    - group: gateway.networking.k8s.io
+      kind: Gateway
+      name: open-webui
+      sectionName: https
+  rules:
+    - backendRefs:
+        - group: ""
+          kind: Service
+          name: open-webui
+          port: 8080
+          weight: 1
+      matches:
+        - path:
+            type: PathPrefix
+            value: /
+      sessionPersistence:
+        type: Cookie
+        cookieName: open-webui-backend
+        absoluteTimeout: 24h0m0s

apps/base/open-webui/kustomization.yaml

@@ -0,0 +1,15 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - namespace.yaml
+  - cnpg_cluster.yaml
+  - cnpg_pooler.yaml
+  - deployment.yaml
+  - pdb.yaml
+  - service.yaml
+  - gateway.yaml
+  - httproute.yaml
+  - vaultauth.yaml
+  - vaultstaticsecret.yaml

apps/base/open-webui/namespace.yaml

@@ -0,0 +1,5 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: open-webui

apps/base/open-webui/pdb.yaml

@@ -0,0 +1,11 @@
+---
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: open-webui
+  namespace: open-webui
+spec:
+  minAvailable: 1
+  selector:
+    matchLabels:
+      app: open-webui

apps/base/open-webui/service.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: open-webui
+  namespace: open-webui
+spec:
+  internalTrafficPolicy: Cluster
+  ports:
+    - name: http
+      port: 8080
+      protocol: TCP
+      targetPort: http
+  selector:
+    app: open-webui
+  sessionAffinity: None
+  type: ClusterIP

apps/base/open-webui/vaultauth.yaml

@@ -0,0 +1,18 @@
+---
+apiVersion: secrets.hashicorp.com/v1beta1
+kind: VaultAuth
+metadata:
+  name: default
+  namespace: open-webui
+spec:
+  allowedNamespaces:
+    - open-webui
+  kubernetes:
+    audiences:
+      - vault
+    role: default
+    serviceAccount: default
+    tokenExpirationSeconds: 600
+  method: kubernetes
+  mount: k8s/au/syd1
+  vaultConnectionRef: vso-system/default

apps/base/open-webui/vaultstaticsecret.yaml

@@ -0,0 +1,34 @@
+---
+apiVersion: secrets.hashicorp.com/v1beta1
+kind: VaultStaticSecret
+metadata:
+  name: postgres-credentials
+  namespace: open-webui
+spec:
+  destination:
+    create: true
+    name: postgres-credentials
+    overwrite: true
+  hmacSecretData: true
+  mount: kv
+  path: kubernetes/namespace/open-webui/default/postgres-credentials
+  refreshAfter: 5m
+  type: kv-v2
+  vaultAuthRef: default
+---
+apiVersion: secrets.hashicorp.com/v1beta1
+kind: VaultStaticSecret
+metadata:
+  name: open-webui-credentials
+  namespace: open-webui
+spec:
+  destination:
+    create: true
+    name: open-webui-credentials
+    overwrite: true
+  hmacSecretData: true
+  mount: kv
+  path: kubernetes/namespace/open-webui/default/open-webui-credentials
+  refreshAfter: 5m
+  type: kv-v2
+  vaultAuthRef: default

apps/overlays/au-syd1/open-webui/kustomization.yaml

@@ -0,0 +1,6 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - ../../../base/open-webui

argocd/applicationsets/aitooling.yaml

@@ -11,6 +11,7 @@ spec:
       revision: HEAD
       directories:
       - path: apps/overlays/*/litellm
+      - path: apps/overlays/*/open-webui
       - path: apps/overlays/*/paperclip
   template:
     metadata:

argocd/projects/aitooling.yaml

@@ -11,6 +11,8 @@ spec:
   destinations:
     - namespace: 'litellm'
       server: https://kubernetes.default.svc
+    - namespace: 'open-webui'
+      server: https://kubernetes.default.svc
     - namespace: 'paperclip'
       server: https://kubernetes.default.svc
   clusterResourceWhitelist: