Allow node IP to be passed as optional config for kubelet

In case of multiple IPs on the node, this will allow admin to
specify desired IP to be used for the node.

cmd/kubelet/app/server.go

@@ -158,6 +158,7 @@ type KubeletServer struct {
 	// Pull images one at a time.
 	SerializeImagePulls        bool
 	ExperimentalFlannelOverlay bool
+	NodeIP                     net.IP
 }
 
 // bootstrapping interface for kubelet, targets the initialization protocol
@@ -349,6 +350,7 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.IntVar(&s.KubeAPIBurst, "kube-api-burst", s.KubeAPIBurst, "Burst to use while talking with kubernetes apiserver")
 	fs.BoolVar(&s.SerializeImagePulls, "serialize-image-pulls", s.SerializeImagePulls, "Pull images one at a time. We recommend *not* changing the default value on nodes that run docker daemon with version < 1.9 or an Aufs storage backend. Issue #10959 has more details. [default=true]")
 	fs.BoolVar(&s.ExperimentalFlannelOverlay, "experimental-flannel-overlay", s.ExperimentalFlannelOverlay, "Experimental support for starting the kubelet with the default overlay network (flannel). Assumes flanneld is already running in client mode. [default=false]")
+	fs.IPVar(&s.NodeIP, "node-ip", s.NodeIP, "IP address of the node. If set, kubelet will use this IP address for the node")
 }
 
 // UnsecuredKubeletConfig returns a KubeletConfig suitable for being run, or an error if the server setup
@@ -488,6 +490,7 @@ func (s *KubeletServer) UnsecuredKubeletConfig() (*KubeletConfig, error) {
 		VolumePlugins:                  ProbeVolumePlugins(s.VolumePluginDir),
 
 		ExperimentalFlannelOverlay: s.ExperimentalFlannelOverlay,
+		NodeIP: s.NodeIP,
 	}, nil
 }
 
@@ -964,6 +967,7 @@ type KubeletConfig struct {
 	VolumePlugins                  []volume.VolumePlugin
 
 	ExperimentalFlannelOverlay bool
+	NodeIP                     net.IP
 }
 
 func CreateAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.PodConfig, err error) {
@@ -1047,6 +1051,7 @@ func CreateAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.Pod
 		kc.SerializeImagePulls,
 		kc.ContainerManager,
 		kc.ExperimentalFlannelOverlay,
+		kc.NodeIP,
 	)
 
 	if err != nil {