Setup kernel support

internal/app/wwctl/kernel/build/main.go

@@ -0,0 +1,55 @@
+package build
+
+import (
+	"github.com/hpcng/warewulf/internal/pkg/assets"
+	"github.com/hpcng/warewulf/internal/pkg/kernel"
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"github.com/spf13/cobra"
+	"os"
+)
+
+func CobraRunE(cmd *cobra.Command, args []string) error {
+	var nodes []assets.NodeInfo
+	set := make(map[string]int)
+
+	if len(args) == 1 && ByNode == true {
+		var err error
+		nodes, err = assets.SearchByName(args[0])
+		if err != nil {
+			wwlog.Printf(wwlog.ERROR, "Could not find nodes for search term: %s\n", args[0])
+			os.Exit(1)
+		}
+
+		for _, node := range nodes {
+			set[node.KernelVersion] ++
+		}
+
+	} else if BuildAll == true {
+		var err error
+		nodes, err = assets.FindAllNodes()
+		if err != nil {
+			wwlog.Printf(wwlog.ERROR, "Could not get list of nodes: %s\n", err)
+			os.Exit(1)
+		}
+
+		for _, node := range nodes {
+			set[node.KernelVersion] ++
+		}
+
+	} else if len(args) == 1 {
+		set[args[0]] ++
+	} else {
+		cmd.Usage()
+		os.Exit(1)
+	}
+
+	for k := range set {
+		err := kernel.Build(k)
+		if err != nil {
+			wwlog.Printf(wwlog.ERROR, "%s\n", err)
+			os.Exit(1)
+		}
+	}
+
+	return nil
+}