add build tags to legacy provider code and make it possible to build kube-controller-manager without any legacyproviders or without particular legacy providers

pkg/controller/nodeipam/node_ipam_controller.go

@@ -28,14 +28,13 @@ import (
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/record"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	coreinformers "k8s.io/client-go/informers/core/v1"
 	clientset "k8s.io/client-go/kubernetes"
 	corelisters "k8s.io/client-go/listers/core/v1"
 	cloudprovider "k8s.io/cloud-provider"
 	"k8s.io/kubernetes/pkg/controller"
 	"k8s.io/kubernetes/pkg/controller/nodeipam/ipam"
-	nodesync "k8s.io/kubernetes/pkg/controller/nodeipam/ipam/sync"
 	"k8s.io/kubernetes/pkg/util/metrics"
 )
 
@@ -131,33 +130,7 @@ func NewNodeIpamController(
 
 	// TODO: Abstract this check into a generic controller manager should run method.
 	if ic.allocatorType == ipam.IPAMFromClusterAllocatorType || ic.allocatorType == ipam.IPAMFromCloudAllocatorType {
-		cfg := &ipam.Config{
-			Resync:       ipamResyncInterval,
-			MaxBackoff:   ipamMaxBackoff,
-			InitialRetry: ipamInitialBackoff,
-		}
-		switch ic.allocatorType {
-		case ipam.IPAMFromClusterAllocatorType:
-			cfg.Mode = nodesync.SyncFromCluster
-		case ipam.IPAMFromCloudAllocatorType:
-			cfg.Mode = nodesync.SyncFromCloud
-		}
-
-		// we may end up here with no cidr at all in case of FromCloud/FromCluster
-		var cidr *net.IPNet
-		if len(clusterCIDRs) > 0 {
-			cidr = clusterCIDRs[0]
-		}
-		if len(clusterCIDRs) > 1 {
-			klog.Warningf("Multiple cidrs were configured with FromCluster or FromCloud. cidrs except first one were discarded")
-		}
-		ipamc, err := ipam.NewController(cfg, kubeClient, cloud, cidr, serviceCIDR, nodeCIDRMaskSize)
-		if err != nil {
-			klog.Fatalf("Error creating ipam controller: %v", err)
-		}
-		if err := ipamc.Start(nodeInformer); err != nil {
-			klog.Fatalf("Error trying to Init(): %v", err)
-		}
+		startLegacyIPAM(ic, nodeInformer, cloud, kubeClient, clusterCIDRs, serviceCIDR, nodeCIDRMaskSize)
 	} else {
 		var err error
 		ic.cidrAllocator, err = ipam.New(kubeClient, cloud, nodeInformer, ic.allocatorType, clusterCIDRs, ic.serviceCIDR, nodeCIDRMaskSize)