grpc: set localhost Authority to unix client calls

Several reports exist (both with device plugins and CSI) that
kubelet w/ grpc-go sends invalid Authority header and some non
grpc-go servers reject these unix domain socket client connections.

grpc-go sets the Authority header correct when the dial address
is in a format where the its address scheme can be determined.

Instead of making changes to get the all server addresses to unix://
prefixed format, set grpc.WithAuthority("localhost") client connection
override to get the same result.

Signed-off-by: Mikko Ylinen <mikko.ylinen@intel.com>

pkg/kubelet/cm/devicemanager/plugin/v1beta1/client.go

@@ -119,6 +119,7 @@ func dial(unixSocketPath string) (api.DevicePluginClient, *grpc.ClientConn, erro
 	defer cancel()
 
 	c, err := grpc.DialContext(ctx, unixSocketPath,
+		grpc.WithAuthority("localhost"),
 		grpc.WithTransportCredentials(insecure.NewCredentials()),
 		grpc.WithBlock(),
 		grpc.WithContextDialer(func(ctx context.Context, addr string) (net.Conn, error) {

pkg/volume/csi/csi_client.go

@@ -535,6 +535,7 @@ func newGrpcConn(addr csiAddr, metricsManager *MetricsManager) (*grpc.ClientConn
 
 	return grpc.Dial(
 		string(addr),
+		grpc.WithAuthority("localhost"),
 		grpc.WithTransportCredentials(insecure.NewCredentials()),
 		grpc.WithContextDialer(func(ctx context.Context, target string) (net.Conn, error) {
 			return (&net.Dialer{}).DialContext(ctx, network, target)