Skip node cidr mask size check for cloud allocation.

Unittest added for node_ipan_controller.go.

pkg/controller/nodeipam/BUILD

@@ -3,6 +3,23 @@ package(default_visibility = ["//visibility:public"])
 load(
     "@io_bazel_rules_go//go:def.bzl",
     "go_library",
+    "go_test",
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["node_ipam_controller_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//pkg/cloudprovider/providers/gce:go_default_library",
+        "//pkg/controller:go_default_library",
+        "//pkg/controller/nodeipam/ipam:go_default_library",
+        "//pkg/controller/testutil:go_default_library",
+        "//staging/src/k8s.io/api/core/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/client-go/informers:go_default_library",
+        "//staging/src/k8s.io/client-go/kubernetes/fake:go_default_library",
+    ],
 )
 
 go_library(

pkg/controller/nodeipam/node_ipam_controller.go

@@ -110,8 +110,11 @@ func NewNodeIpamController(
 		glog.Fatal("Controller: Must specify --cluster-cidr if --allocate-node-cidrs is set")
 	}
 	mask := clusterCIDR.Mask
-	if maskSize, _ := mask.Size(); maskSize > nodeCIDRMaskSize {
-		glog.Fatal("Controller: Invalid --cluster-cidr, mask size of cluster CIDR must be less than --node-cidr-mask-size")
+	if allocatorType != ipam.CloudAllocatorType {
+		// Cloud CIDR allocator does not rely on clusterCIDR or nodeCIDRMaskSize for allocation.
+		if maskSize, _ := mask.Size(); maskSize > nodeCIDRMaskSize {
+			glog.Fatal("Controller: Invalid --cluster-cidr, mask size of cluster CIDR must be less than --node-cidr-mask-size")
+		}
 	}
 
 	ic := &Controller{

pkg/controller/nodeipam/node_ipam_controller_test.go

@@ -0,0 +1,102 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package nodeipam
+
+import (
+	"net"
+	"os"
+	"os/exec"
+	"testing"
+
+	"k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes/fake"
+	"k8s.io/kubernetes/pkg/cloudprovider/providers/gce"
+	"k8s.io/kubernetes/pkg/controller"
+	"k8s.io/kubernetes/pkg/controller/nodeipam/ipam"
+	"k8s.io/kubernetes/pkg/controller/testutil"
+)
+
+func newTestNodeIpamController(clusterCIDR, serviceCIDR *net.IPNet, nodeCIDRMaskSize int, allocatorType ipam.CIDRAllocatorType) (*Controller, error) {
+	clientSet := fake.NewSimpleClientset()
+	fakeNodeHandler := &testutil.FakeNodeHandler{
+		Existing: []*v1.Node{
+			{ObjectMeta: metav1.ObjectMeta{Name: "node0"}},
+		},
+		Clientset: fake.NewSimpleClientset(),
+	}
+	fakeClient := &fake.Clientset{}
+	fakeInformerFactory := informers.NewSharedInformerFactory(fakeClient, controller.NoResyncPeriodFunc())
+	fakeNodeInformer := fakeInformerFactory.Core().V1().Nodes()
+
+	for _, node := range fakeNodeHandler.Existing {
+		fakeNodeInformer.Informer().GetStore().Add(node)
+	}
+
+	fakeGCE := gce.FakeGCECloud(gce.DefaultTestClusterValues())
+	return NewNodeIpamController(
+		fakeNodeInformer, fakeGCE, clientSet,
+		clusterCIDR, serviceCIDR, nodeCIDRMaskSize, allocatorType,
+	)
+}
+
+// TestNewNodeIpamControllerWithCIDRMasks tests if the controller can be
+// created with combinations of network CIDRs and masks.
+func TestNewNodeIpamControllerWithCIDRMasks(t *testing.T) {
+	for _, tc := range []struct {
+		desc          string
+		clusterCIDR   string
+		serviceCIDR   string
+		maskSize      int
+		allocatorType ipam.CIDRAllocatorType
+		wantFatal     bool
+	}{
+		{"valid_range_allocator", "10.0.0.0/21", "10.1.0.0/21", 24, ipam.RangeAllocatorType, false},
+		{"valid_cloud_allocator", "10.0.0.0/21", "10.1.0.0/21", 24, ipam.CloudAllocatorType, false},
+		{"valid_ipam_from_cluster", "10.0.0.0/21", "10.1.0.0/21", 24, ipam.IPAMFromClusterAllocatorType, false},
+		{"valid_ipam_from_cloud", "10.0.0.0/21", "10.1.0.0/21", 24, ipam.IPAMFromCloudAllocatorType, false},
+		{"invalid_cluster_CIDR", "invalid", "10.1.0.0/21", 24, ipam.CloudAllocatorType, true},
+		{"valid_CIDR_smaller_than_mask_cloud_allocator", "10.0.0.0/26", "10.1.0.0/21", 24, ipam.CloudAllocatorType, false},
+		{"invalid_CIDR_smaller_than_mask_other_allocators", "10.0.0.0/26", "10.1.0.0/21", 24, ipam.IPAMFromCloudAllocatorType, true},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			_, clusterCIDRIpNet, _ := net.ParseCIDR(tc.clusterCIDR)
+			_, serviceCIDRIpNet, _ := net.ParseCIDR(tc.serviceCIDR)
+			if os.Getenv("EXIT_ON_FATAL") == "1" {
+				// This is the subprocess which runs the actual code.
+				newTestNodeIpamController(clusterCIDRIpNet, serviceCIDRIpNet, tc.maskSize, tc.allocatorType)
+				return
+			}
+			// This is the host process that monitors the exit code of the subprocess.
+			cmd := exec.Command(os.Args[0], "-test.run=TestNewNodeIpamControllerWithCIDRMasks/"+tc.desc)
+			cmd.Env = append(os.Environ(), "EXIT_ON_FATAL=1")
+			err := cmd.Run()
+			var gotFatal bool
+			if err != nil {
+				exitErr, ok := err.(*exec.ExitError)
+				if !ok {
+					t.Fatalf("Failed to run subprocess: %v", err)
+				}
+				gotFatal = !exitErr.Success()
+			}
+			if gotFatal != tc.wantFatal {
+				t.Errorf("newTestNodeIpamController(%v, %v, %v, %v) : gotFatal = %t ; wantFatal = %t", clusterCIDRIpNet, serviceCIDRIpNet, tc.maskSize, tc.allocatorType, gotFatal, tc.wantFatal)
+			}
+		})
+	}
+}