created exports with template

internal/pkg/configure/nfs.go

@@ -4,12 +4,17 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/hpcng/warewulf/internal/pkg/overlay"
 	"github.com/hpcng/warewulf/internal/pkg/util"
 	"github.com/hpcng/warewulf/internal/pkg/warewulfconf"
 	"github.com/hpcng/warewulf/internal/pkg/wwlog"
 	"github.com/pkg/errors"
 )
 
+/*
+Creates '/etc/exports' from the host template, enables and start the 
+nfs server.
+*/
 func configureNFS() error {
 
 	controller, err := warewulfconf.New()
@@ -19,19 +24,13 @@ func configureNFS() error {
 	}
 
 	if controller.Nfs.Enabled {
-		exports, err := os.OpenFile("/etc/exports", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
 		if err != nil {
-			wwlog.Printf(wwlog.ERROR, "%s\n", err)
-			os.Exit(1)
+			fmt.Println(err)
 		}
-		defer exports.Close()
-
-		fmt.Fprintf(exports, "# This file was written by Warewulf (wwctl configure nfs)\n")
-
-		for _, export := range controller.Nfs.ExportsExtended {
-			fmt.Fprintf(exports, "%s %s/%s(%s)\n", export.Path, controller.Network, controller.Netmask, export.ExportOptions)
+		err = overlay.BuildHostOverlay()
+    if err != nil {
+			wwlog.Printf(wwlog.WARN, "host overlay could not be built: %s\n", err)
 		}
-
 		fmt.Printf("Enabling and restarting the NFS services\n")
 		if controller.Nfs.SystemdName == "" {
 			err := util.SystemdStart("nfs-server")
@@ -49,6 +48,10 @@ func configureNFS() error {
 	return nil
 }
 
+/*
+Prints the configured nfs exports in formated style, needs not to be 
+the content of '/etc/exports'
+*/
 func showNFS() {
 	controller, err := warewulfconf.New()
 	if err != nil {