Attempt overlayfs to have smaller PVCs

Signed-off-by: Martyn Ranyard <m@rtyn.berlin>

apps-helm/samba4/conf/smb.conf

@@ -33,4 +33,12 @@
     browseable = {{ .browseable | default "yes" }}
     writable = {{ .writable | default "yes" }}
 {{- end }}
+
+{{ if .Values.persistence.combineShares }}{{ range .Values.persistence.sharesToCombine }}
+[{{ .destName }}]
+    path = /combined/{{ .destName }}
+    comment = Magic combined share
+    browseable = yes
+    writable = yes
+{{- end }}{{ end }}
 ;EOF way past actual end of file

apps-helm/samba4/templates/deployment.yaml

@@ -40,6 +40,28 @@ spec:
         {{- toYaml . | nindent 8 }}
       {{- end }}
       containers:
+{{- if .Values.persistence.combineShares }}
+        - name: overlaymagic
+          image: busybox
+          command:
+          - /bin/sh
+          - -c
+          - --
+          args:
+          {{- range .Values.persistence.sharesToCombine }}
+          - mkdir -p /combined/{{ .destName }};
+            mkdir -p /data/overlay-{{ .destName }};
+            mount -t overlay -o lowerdir={{ join ":" .shares }},upperdir=/data/overlay-{{ .destName }}-upper,workdir=/data/overlay/{{ .destName }}-work overlay /combined/{{ .destName }};
+            sleep infinity;
+          {{- end }}
+          lifecycle:
+            preStop:
+              exec:
+                command:
+                - /bin/sh
+                - -c
+                - {{ range  .Values.persistence.sharesToCombine }}umount /combined/{{ .destName }}; {{- end }}
+{{- end }}
         - name: {{ .Chart.Name }}
           image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
           command:

apps-helm/samba4/values.yaml

@@ -38,6 +38,10 @@ persistence:
   other:
     emptyDir: {}
   extraPVCShares: []
+  combineShares: false
+  sharesToCombine:
+  - destName: ""
+    shares: []
 
 privatePersistence:
   enabled: false