add support for using an existing claim for volume server

k8s/charts/seaweedfs/templates/volume-statefulset.yaml

@@ -227,18 +227,33 @@ spec:
             path: {{ .Values.volume.data.hostPathPrefix }}/object_store/
             type: DirectoryOrCreate
         {{- end }}
+        {{- if eq .Values.volume.data.type "existingClaim" }}
+        - name: data
+          persistentVolumeClaim:
+            claimName: {{ .Values.volume.data.claimName }} 
+        {{- end }}
         {{- if and (eq .Values.volume.idx.type "hostPath") .Values.volume.dir_idx }}
         - name: idx
           hostPath:
             path: {{ .Values.volume.idx.hostPathPrefix }}/seaweedfs-volume-idx/
             type: DirectoryOrCreate
         {{- end }}
+        {{- if eq .Values.volume.idx.type "existingClaim" }}
+        - name: data
+          persistentVolumeClaim:
+            claimName: {{ .Values.volume.idx.claimName }} 
+        {{- end }}
         {{- if eq .Values.volume.logs.type "hostPath" }}
         - name: logs
           hostPath:
             path: {{ .Values.volume.logs.hostPathPrefix }}/logs/seaweedfs/volume
             type: DirectoryOrCreate
         {{- end }}
+        {{- if eq .Values.volume.logs.type "existingClaim" }}
+        - name: data
+          persistentVolumeClaim:
+            claimName: {{ .Values.volume.data.claimName }} 
+        {{- end }}
         {{- if .Values.global.enableSecurity }}
         - name: security-config
           configMap: