Merge pull request kubernetes#39440 from apprenda/kubeadm_102-fix_proxy

Automatic merge from submit-queue (batch tested with PRs 40574, 40806, 40308, 40771, 39440)

kubeadm: kube-proxy needs to know the pod subnet CIDR

**What this PR does / why we need it**: `kube-proxy` 1.5 has a new flag `cluster-cidr` that isn't specified by `kubeadm`, thus resulting in bug kubernetes/kubeadm#102.

**Which issue this PR fixes**: fixes kubernetes/kubeadm#102

**Special notes for your reviewer**:
/cc @luxas @dmmcquay

cmd/kubeadm/app/master/manifests.go

@@ -425,7 +425,9 @@ func getSchedulerCommand(cfg *kubeadmapi.MasterConfiguration, selfHosted bool) [
 }
 
 func getProxyCommand(cfg *kubeadmapi.MasterConfiguration) []string {
-	return getComponentBaseCommand(proxy)
+	return append(getComponentBaseCommand(proxy),
+		"--cluster-cidr="+cfg.Networking.PodSubnet,
+	)
 }
 
 func getProxyEnvVars() []api.EnvVar {

cmd/kubeadm/app/master/manifests_test.go

@@ -559,9 +559,14 @@ func TestGetProxyCommand(t *testing.T) {
 		expected []string
 	}{
 		{
-			cfg: &kubeadmapi.MasterConfiguration{},
+			cfg: &kubeadmapi.MasterConfiguration{
+				Networking: kubeadm.Networking{
+					PodSubnet: "bar",
+				},
+			},
 			expected: []string{
 				"kube-proxy",
+				"--cluster-cidr=bar",
 			},
 		},
 	}