support pass in kubeconfig and master to client-go by flag

main.go

@@ -14,6 +14,7 @@
 package main
 
 import (
+	"flag"
 	"io"
 	"os"
 
@@ -31,20 +32,28 @@ const (
 )
 
 var (
-	version string
+	version    string
+	kubeconfig string
+	master     string
 )
 
+func init() {
+	flag.StringVar(&master, "master", "", "The address of the Kubernetes API server (overrides any value in kubeconfig).")
+	flag.StringVar(&kubeconfig, "kubeconfig", "", "Path to kubeconfig file with authorization and master location information.")
+}
+
 func main() {
 	os.Exit(_main())
 }
 
 func _main() int {
 	defer log.Flush()
+	flag.Parse()
 	logger.SetupLogger(logger.GetLogFileLocation(defaultLogFilePath))
 
 	log.Infof("Starting L-IPAMD %s  ...", version)
 
-	kubeClient, err := k8sapi.CreateKubeClient()
+	kubeClient, err := k8sapi.CreateKubeClient(kubeconfig, master)
 	if err != nil {
 		log.Errorf("Failed to create client: %v", err)
 		return 1

pkg/k8sapi/discovery.go

@@ -8,19 +8,20 @@ import (
 	"sync"
 	"time"
 
+	"github.com/operator-framework/operator-sdk/pkg/k8sclient"
 	"github.com/pkg/errors"
 
 	log "github.com/cihub/seelog"
 
 	clientset "k8s.io/client-go/kubernetes"
 
-	"github.com/operator-framework/operator-sdk/pkg/k8sclient"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/workqueue"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -80,8 +81,21 @@ func NewController(clientset kubernetes.Interface) *Controller {
 }
 
 // CreateKubeClient creates a k8s client
-func CreateKubeClient() (clientset.Interface, error) {
-	kubeClient := k8sclient.GetKubeClient()
+func CreateKubeClient(kubeconfig, master string) (clientset.Interface, error) {
+	var kubeClient clientset.Interface
+	if master == "" && kubeconfig == "" {
+		kubeClient = k8sclient.GetKubeClient()
+	} else {
+		config, err := clientcmd.BuildConfigFromFlags(master, kubeconfig)
+		if err != nil {
+			panic(err)
+		}
+		kubeClient, err = clientset.NewForConfig(config)
+		if err != nil {
+			panic(err)
+		}
+	}
+
 	// Informers don't seem to do a good job logging error messages when it
 	// can't reach the server, making debugging hard. This makes it easier to
 	// figure out if apiserver is configured incorrectly.