Merge pull request kubernetes#66138 from wsong/fix_proxy_healthz

Automatic merge from submit-queue (batch tested with PRs 66138, 65951). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Don't validate HealthzBindAddress in KubeProxyConfiguration if it's empty

**What this PR does / why we need it**:
kubernetes#49087 added validation for
the HealthzBindAddress field in the KubeProxyConfiguration, but if you pass in
--healthz-port=0 to the kube-proxy CLI, it sets this field to the empty string.
However, an empty string is not a valid value for this field.

This change allows validation to pass if HealthzBindAddress is empty.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Ref kubernetes#65118

**Special notes for your reviewer**:

**Release note**:

```release-note
Fix validation for HealthzBindAddress in kube-proxy when --healthz-port is set to 0
```

pkg/proxy/apis/kubeproxyconfig/validation/validation.go

@@ -60,7 +60,9 @@ func Validate(config *kubeproxyconfig.KubeProxyConfiguration) field.ErrorList {
 		allErrs = append(allErrs, field.Invalid(newPath.Child("BindAddress"), config.BindAddress, "not a valid textual representation of an IP address"))
 	}
 
-	allErrs = append(allErrs, validateHostPort(config.HealthzBindAddress, newPath.Child("HealthzBindAddress"))...)
+	if config.HealthzBindAddress != "" {
+		allErrs = append(allErrs, validateHostPort(config.HealthzBindAddress, newPath.Child("HealthzBindAddress"))...)
+	}
 	allErrs = append(allErrs, validateHostPort(config.MetricsBindAddress, newPath.Child("MetricsBindAddress"))...)
 
 	if config.ClusterCIDR != "" {

pkg/proxy/apis/kubeproxyconfig/validation/validation_test.go

@@ -82,6 +82,26 @@ func TestValidateKubeProxyConfiguration(t *testing.T) {
 				TCPCloseWaitTimeout:   &metav1.Duration{Duration: 5 * time.Second},
 			},
 		},
+		{
+			BindAddress:        "192.168.59.103",
+			HealthzBindAddress: "",
+			MetricsBindAddress: "127.0.0.1:10249",
+			ClusterCIDR:        "192.168.59.0/24",
+			UDPIdleTimeout:     metav1.Duration{Duration: 1 * time.Second},
+			ConfigSyncPeriod:   metav1.Duration{Duration: 1 * time.Second},
+			IPTables: kubeproxyconfig.KubeProxyIPTablesConfiguration{
+				MasqueradeAll: true,
+				SyncPeriod:    metav1.Duration{Duration: 5 * time.Second},
+				MinSyncPeriod: metav1.Duration{Duration: 2 * time.Second},
+			},
+			Conntrack: kubeproxyconfig.KubeProxyConntrackConfiguration{
+				Max:        pointer.Int32Ptr(2),
+				MaxPerCore: pointer.Int32Ptr(1),
+				Min:        pointer.Int32Ptr(1),
+				TCPEstablishedTimeout: &metav1.Duration{Duration: 5 * time.Second},
+				TCPCloseWaitTimeout:   &metav1.Duration{Duration: 5 * time.Second},
+			},
+		},
 	}
 
 	for _, successCase := range successCases {