Move some boiler plate startup logic to nodeutil

This makes a controller that handles the startup for the node and pod
controller.
Later if we add an "api controller" it can also be added here.

This is just part of reducing some of the boiler plate code so it is
easier to get off of node-cli.

node/node.go

@@ -84,6 +84,7 @@ func NewNodeController(p NodeProvider, node *corev1.Node, nodes v1.NodeInterface
 		serverNode: node,
 		nodes:      nodes,
 		chReady:    make(chan struct{}),
+		chDone:     make(chan struct{}),
 	}
 	for _, o := range opts {
 		if err := o(n); err != nil {
@@ -223,7 +224,12 @@ type NodeController struct { // nolint:golint
 
 	nodeStatusUpdateErrorHandler ErrorHandler
 
+	// chReady is closed once the controller is ready to start the control loop
 	chReady chan struct{}
+	// chDone is closed once the control loop has exited
+	chDone chan struct{}
+	errMu  sync.Mutex
+	err    error
 
 	nodePingController *nodePingController
 	pingTimeout        *time.Duration
@@ -249,7 +255,14 @@ const (
 // node status update (because some things still expect the node to be updated
 // periodically), otherwise it will only use node status update with the configured
 // ping interval.
-func (n *NodeController) Run(ctx context.Context) error {
+func (n *NodeController) Run(ctx context.Context) (retErr error) {
+	defer func() {
+		n.errMu.Lock()
+		n.err = retErr
+		n.errMu.Unlock()
+		close(n.chDone)
+	}()
+
 	n.chStatusUpdate = make(chan *corev1.Node, 1)
 	n.p.NotifyNodeStatus(ctx, func(node *corev1.Node) {
 		n.chStatusUpdate <- node
@@ -273,6 +286,22 @@ func (n *NodeController) Run(ctx context.Context) error {
 	return n.controlLoop(ctx, providerNode)
 }
 
+// Done signals to the caller when the controller is done and the control loop is exited.
+//
+// Call n.Err() to find out if there was an error.
+func (n *NodeController) Done() <-chan struct{} {
+	return n.chDone
+}
+
+// Err returns any errors that have occurred that trigger the control loop to exit.
+//
+// Err only returns a non-nil error after `<-n.Done()` returns.
+func (n *NodeController) Err() error {
+	n.errMu.Lock()
+	defer n.errMu.Unlock()
+	return n.err
+}
+
 func (n *NodeController) ensureNode(ctx context.Context, providerNode *corev1.Node) (err error) {
 	ctx, span := trace.StartSpan(ctx, "node.ensureNode")
 	defer span.End()
@@ -307,14 +336,12 @@ func (n *NodeController) ensureNode(ctx context.Context, providerNode *corev1.No
 
 // Ready returns a channel that gets closed when the node is fully up and
 // running. Note that if there is an error on startup this channel will never
-// be started.
+// be closed.
 func (n *NodeController) Ready() <-chan struct{} {
 	return n.chReady
 }
 
 func (n *NodeController) controlLoop(ctx context.Context, providerNode *corev1.Node) error {
-	close(n.chReady)
-
 	defer n.group.Wait()
 
 	var sleepInterval time.Duration
@@ -355,6 +382,7 @@ func (n *NodeController) controlLoop(ctx context.Context, providerNode *corev1.N
 		return false
 	}
 
+	close(n.chReady)
 	for {
 		shouldTerminate := loop()
 		if shouldTerminate {