Add postgres-mcp Helm chart

Wraps FreePeak/db-mcp-server: multi-database Postgres MCP driven by a
single JSON connection list, so new databases don't need a new Helm
release. Includes per-connection read_only/max_rows/query_timeout/
masking_rules guardrails and a PVC-backed audit log.

postgres-mcp/Chart.yaml

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+apiVersion: v2
+name: postgres-mcp
+description: Multi-database Postgres MCP server Helm chart (FreePeak/db-mcp-server)
+type: application
+version: 0.1.0
+appVersion: "1.9.0"
+annotations:
+  version-source: github-release:FreePeak/db-mcp-server
+  version-pattern: "s|^v||"

postgres-mcp/templates/deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: {{ .Release.Name }}
+  labels:
+    app.kubernetes.io/name: {{ .Chart.Name }}
+    app.kubernetes.io/instance: {{ .Release.Name }}
+    app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
+    app.kubernetes.io/component: mcp
+    app.kubernetes.io/part-of: postgres
+  annotations:
+    version-source: {{ index .Chart.Annotations "version-source" }}
+    version-pattern: {{ index .Chart.Annotations "version-pattern" | quote }}
+spec:
+  replicas: 1
+  strategy:
+    # Not RollingUpdate: two pods would both hold live connections against
+    # the same shared mcp_agent role/config at once, doubling connection
+    # count and audit-log writers for no benefit -- this server has no
+    # per-replica state to preserve, so a brief gap during redeploy is fine.
+    type: Recreate
+  selector:
+    matchLabels:
+      app: {{ .Release.Name }}
+  template:
+    metadata:
+      labels:
+        app: {{ .Release.Name }}
+    spec:
+      {{- with .Values.nodeSelector }}
+      nodeSelector:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
+      {{- with .Values.tolerations }}
+      tolerations:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
+      containers:
+        - name: {{ .Chart.Name }}
+          image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
+          ports:
+            - containerPort: {{ .Values.port }}
+              name: http
+              protocol: TCP
+          env:
+            {{- range $key, $value := .Values.env }}
+            - name: {{ $key }}
+              value: {{ $value | quote }}
+            {{- end }}
+            {{- if .Values.existingSecret }}
+            - name: DB_CONFIG
+              valueFrom:
+                secretKeyRef:
+                  name: {{ .Values.existingSecret }}
+                  key: {{ .Values.secretConfigKey }}
+            {{- end }}
+            {{- if .Values.auditLog.enabled }}
+            - name: DB_MCP_AUDIT_LOG
+              value: {{ .Values.auditLog.path | quote }}
+            {{- end }}
+          {{- if .Values.auditLog.enabled }}
+          volumeMounts:
+            - name: audit-log
+              mountPath: {{ .Values.auditLog.dir }}
+          {{- end }}
+          resources:
+            {{- toYaml .Values.resources | nindent 12 }}
+      {{- if .Values.auditLog.enabled }}
+      volumes:
+        - name: audit-log
+          persistentVolumeClaim:
+            claimName: {{ .Release.Name }}-audit-log
+      {{- end }}

postgres-mcp/templates/ingress.yaml

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+{{- range $name, $config := .Values.ingresses }}
+---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: {{ $.Release.Name }}-{{ $name }}
+  {{- with $config.annotations }}
+  annotations:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+spec:
+  rules:
+    - host: {{ $config.host }}
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: {{ $.Release.Name }}
+                port:
+                  number: {{ $.Values.port }}
+  {{- with $config.tls }}
+  tls:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+{{- end }}

postgres-mcp/templates/pvc.yaml

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+{{- if .Values.auditLog.enabled }}
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: {{ .Release.Name }}-audit-log
+spec:
+  accessModes:
+    - ReadWriteOnce
+  storageClassName: {{ .Values.auditLog.storageClass }}
+  resources:
+    requests:
+      storage: {{ .Values.auditLog.size }}
+{{- end }}

postgres-mcp/templates/service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ .Release.Name }}
+  labels:
+    app.kubernetes.io/name: {{ .Chart.Name }}
+    app.kubernetes.io/instance: {{ .Release.Name }}
+spec:
+  type: ClusterIP
+  selector:
+    app: {{ .Release.Name }}
+  ports:
+    - name: http
+      port: {{ .Values.port }}
+      targetPort: http
+      protocol: TCP

postgres-mcp/values.yaml

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+image:
+  repository: freepeak/db-mcp-server
+  tag: ""
+  pullPolicy: IfNotPresent
+
+port: 9092
+
+# Name of a Secret holding the whole multi-database config as one JSON blob
+# (see FreePeak/db-mcp-server's DB_CONFIG env var) -- keeps connection
+# strings/passwords for every database out of a plain ConfigMap.
+existingSecret: ""
+secretConfigKey: "DB_CONFIG"
+
+env:
+  TRANSPORT_MODE: "sse"
+  SERVER_PORT: "9092"
+  LOG_LEVEL: "info"
+
+# Persistent audit log (DB_MCP_AUDIT_LOG) -- one JSONL record per executed
+# statement, including rejected writes against read-only databases. Kept on
+# a small PVC so it survives pod restarts; this is the primary compensating
+# control for a server with broad read/write reach across many databases.
+auditLog:
+  enabled: true
+  dir: /var/log/db-mcp
+  path: /var/log/db-mcp/audit.jsonl
+  storageClass: local-path
+  size: 1Gi
+
+resources:
+  requests:
+    cpu: "50m"
+    memory: "128Mi"
+  limits:
+    cpu: "500m"
+    memory: "512Mi"
+
+nodeSelector: {}
+
+tolerations: []
+
+ingresses: {}
+  # https:
+  #   host: pg.mcp.example.com
+  #   annotations: {}
+  #   tls:
+  #     - hosts:
+  #         - pg.mcp.example.com
+  # lan:
+  #   host: pg.mcp.example.lan
+  #   annotations: {}