Add provider method to pass node configuration (#680)

This eliminates all the one-off calls to for specific things like
`Capacity` and other things.
Instead we configure defaults in the CLI and then pass the full node
object to the provider to change as needed.

This makes sure the provider can change whatever they need to without
having to add tons of methods to the provider interface.

cmd/virtual-kubelet/commands/root/node.go

@@ -25,6 +25,8 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
+const osLabel = "beta.kubernetes.io/os"
+
 // NodeFromProvider builds a kubernetes node object from a provider
 // This is a temporary solution until node stuff actually split off from the provider interface itself.
 func NodeFromProvider(ctx context.Context, name string, taint *v1.Taint, p providers.Provider, version string) *v1.Node {
@@ -40,9 +42,7 @@ func NodeFromProvider(ctx context.Context, name string, taint *v1.Taint, p provi
 			Labels: map[string]string{
 				"type":                   "virtual-kubelet",
 				"kubernetes.io/role":     "agent",
-				"beta.kubernetes.io/os":  strings.ToLower(p.OperatingSystem()),
 				"kubernetes.io/hostname": name,
-				"alpha.service-controller.kubernetes.io/exclude-balancer": "true",
 			},
 		},
 		Spec: v1.NodeSpec{
@@ -50,17 +50,16 @@ func NodeFromProvider(ctx context.Context, name string, taint *v1.Taint, p provi
 		},
 		Status: v1.NodeStatus{
 			NodeInfo: v1.NodeSystemInfo{
-				OperatingSystem: p.OperatingSystem(),
-				Architecture:    "amd64",
-				KubeletVersion:  version,
+				Architecture:   "amd64",
+				KubeletVersion: version,
 			},
-			Capacity:        p.Capacity(ctx),
-			Allocatable:     p.Capacity(ctx),
-			Conditions:      p.NodeConditions(ctx),
-			Addresses:       p.NodeAddresses(ctx),
-			DaemonEndpoints: *p.NodeDaemonEndpoints(ctx),
 		},
 	}
+
+	p.ConfigureNode(ctx, node)
+	if _, ok := node.ObjectMeta.Labels[osLabel]; !ok {
+		node.ObjectMeta.Labels[osLabel] = strings.ToLower(node.Status.NodeInfo.OperatingSystem)
+	}
 	return node
 }