Makes modes OS-specific (+ fixes tests).

pkg/proxy/apis/kubeproxyconfig/types.go

@@ -152,11 +152,13 @@ type KubeProxyConfiguration struct {
 	ConfigSyncPeriod metav1.Duration
 }
 
-// Currently two modes of proxying are available: 'userspace' (older, stable) or 'iptables'
-// (newer, faster). If blank, use the best-available proxy (currently iptables, but may
-// change in future versions).  If the iptables proxy is selected, regardless of how, but
-// the system's kernel or iptables versions are insufficient, this always falls back to the
-// userspace proxy.
+// Currently, four modes of proxying are available total: 'userspace' (older, stable), 'iptables'
+// (newer, faster), 'ipvs', and 'kernelspace' (Windows only, newer).
+//
+// If blank, use the best-available proxy (currently iptables, but may change in
+// future versions). If the iptables proxy is selected, regardless of how, but
+// the system's kernel or iptables versions are insufficient, this always falls
+// back to the userspace proxy.
 type ProxyMode string
 
 const (

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

@@ -19,6 +19,7 @@ package validation
 import (
 	"fmt"
 	"net"
+	"runtime"
 	"strconv"
 	"strings"
 
@@ -146,11 +147,18 @@ func validateProxyMode(mode kubeproxyconfig.ProxyMode, fldPath *field.Path) fiel
 	case kubeproxyconfig.ProxyModeUserspace:
 	case kubeproxyconfig.ProxyModeIPTables:
 	case kubeproxyconfig.ProxyModeIPVS:
-	case kubeproxyconfig.ProxyModeKernelspace:
 	case "":
+	case kubeproxyconfig.ProxyModeKernelspace:
+		if runtime.GOOS != "windows" {
+			errMsg := fmt.Sprintf("%s is only supported on Windows", string(kubeproxyconfig.ProxyModeKernelspace))
+			allErrs = append(allErrs, field.Invalid(fldPath.Child("ProxyMode"), string(mode), errMsg))
+		}
 	default:
-		modes := []string{string(kubeproxyconfig.ProxyModeUserspace), string(kubeproxyconfig.ProxyModeIPTables), string(kubeproxyconfig.ProxyModeIPVS), string(kubeproxyconfig.ProxyModeKernelspace)}
-		errMsg := fmt.Sprintf("must be %s or blank (blank means the best-available proxy (currently iptables)", strings.Join(modes, ","))
+		modes := []string{string(kubeproxyconfig.ProxyModeUserspace), string(kubeproxyconfig.ProxyModeIPTables), string(kubeproxyconfig.ProxyModeIPVS)}
+		if runtime.GOOS == "windows" {
+			modes = append(modes, string(kubeproxyconfig.ProxyModeKernelspace))
+		}
+		errMsg := fmt.Sprintf("must be %s or blank (blank means the best-available proxy [currently iptables])", strings.Join(modes, ","))
 		allErrs = append(allErrs, field.Invalid(fldPath.Child("ProxyMode"), string(mode), errMsg))
 	}
 	return allErrs

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

@@ -18,6 +18,7 @@ package validation
 
 import (
 	"fmt"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -488,11 +489,15 @@ func TestValidateProxyMode(t *testing.T) {
 	newPath := field.NewPath("KubeProxyConfiguration")
 	successCases := []kubeproxyconfig.ProxyMode{
 		kubeproxyconfig.ProxyModeUserspace,
-		kubeproxyconfig.ProxyModeIPTables,
-		kubeproxyconfig.ProxyModeIPVS,
 		kubeproxyconfig.ProxyMode(""),
 	}
 
+	if runtime.GOOS == "windows" {
+		successCases = append(successCases, kubeproxyconfig.ProxyModeKernelspace)
+	} else {
+		successCases = append(successCases, kubeproxyconfig.ProxyModeIPTables, kubeproxyconfig.ProxyModeIPVS)
+	}
+
 	for _, successCase := range successCases {
 		if errs := validateProxyMode(successCase, newPath.Child("ProxyMode")); len(errs) != 0 {
 			t.Errorf("expected success: %v", errs)
@@ -505,13 +510,13 @@ func TestValidateProxyMode(t *testing.T) {
 	}{
 		{
 			mode: kubeproxyconfig.ProxyMode("non-existing"),
-			msg:  "or blank (blank means the best-available proxy (currently iptables)",
+			msg:  "or blank (blank means the best-available proxy [currently iptables])",
 		},
 	}
 
 	for _, errorCase := range errorCases {
 		if errs := validateProxyMode(errorCase.mode, newPath.Child("ProxyMode")); len(errs) == 0 {
-			t.Errorf("expected failure for %s", errorCase.msg)
+			t.Errorf("expected failure %s for %v", errorCase.msg, errorCase.mode)
 		} else if !strings.Contains(errs[0].Error(), errorCase.msg) {
 			t.Errorf("unexpected error: %v, expected: %s", errs[0], errorCase.msg)
 		}