Allow GCE network to be reconfigured

pkg/model/gcemodel/context.go

@@ -28,8 +28,18 @@ type GCEModelContext struct {
 	*model.KopsModelContext
 }
 
-func (b *GCEModelContext) LinkToNetwork() *gcetasks.Network {
-	return &gcetasks.Network{Name: s("default")}
+// LinkToNetwork returns the GCE Network object the cluster is located in
+func (c *GCEModelContext) LinkToNetwork() *gcetasks.Network {
+	return &gcetasks.Network{Name: s(c.NameForNetwork())}
+}
+
+// NameForNetwork returns the name for the GCE Network the cluster is located in
+func (c *GCEModelContext) NameForNetwork() string {
+	networkName := c.Cluster.Spec.NetworkID
+	if networkName == "" {
+		networkName = "default"
+	}
+	return networkName
 }
 
 // SafeObjectName returns the object name and cluster name escaped for GCE

pkg/model/gcemodel/network.go

@@ -31,7 +31,7 @@ var _ fi.ModelBuilder = &NetworkModelBuilder{}
 
 func (b *NetworkModelBuilder) Build(c *fi.ModelBuilderContext) error {
 	network := &gcetasks.Network{
-		Name:      s("default"),
+		Name:      s(b.NameForNetwork()),
 		Lifecycle: b.Lifecycle,
 		Mode:      "auto", // Automatically create subnets, but stop using legacy mode
 	}