Merge pull request #56390 from m1093782566/test-mode

Automatic merge from submit-queue. 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>.

Test Proxy Mode

**What this PR does / why we need it**:

Currently, IPVS-based kube-proxy is protected by feature gateway and there is no UT for it. We should test ipvs proxy mode when feature gateway is set.

**Which issue(s) this PR fixes**:
Fixes #56404

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

pkg/proxy/ipvs/proxier.go

@@ -688,14 +688,28 @@ func (em proxyEndpointsMap) unmerge(other proxyEndpointsMap) {
 	}
 }
 
-// CanUseIPVSProxier returns true if we can use the ipvs Proxier.
-// This is determined by checking if all the required kernel modules can be loaded. It may
-// return an error if it fails to get the kernel modules information without error, in which
-// case it will also return false.
-func CanUseIPVSProxier(ipsetver IPSetVersioner) (bool, error) {
-	// Try to load IPVS required kernel modules using modprobe
+// KernelHandler can handle the current installed kernel modules.
+type KernelHandler interface {
+	GetModules() ([]string, error)
+}
+
+// LinuxKernelHandler implements KernelHandler interface.
+type LinuxKernelHandler struct {
+	executor utilexec.Interface
+}
+
+// NewLinuxKernelHandler initializes LinuxKernelHandler with exec.
+func NewLinuxKernelHandler() *LinuxKernelHandler {
+	return &LinuxKernelHandler{
+		executor: utilexec.New(),
+	}
+}
+
+// GetModules returns all installed kernel modules.
+func (handle *LinuxKernelHandler) GetModules() ([]string, error) {
+	// Try to load IPVS required kernel modules using modprobe first
 	for _, kmod := range ipvsModules {
-		err := utilexec.New().Command("modprobe", "--", kmod).Run()
+		err := handle.executor.Command("modprobe", "--", kmod).Run()
 		if err != nil {
 			glog.Warningf("Failed to load kernel module %v with modprobe. "+
 				"You can ignore this message when kube-proxy is running inside container without mounting /lib/modules", kmod)
@@ -703,12 +717,24 @@ func CanUseIPVSProxier(ipsetver IPSetVersioner) (bool, error) {
 	}
 
 	// Find out loaded kernel modules
-	out, err := utilexec.New().Command("cut", "-f1", "-d", " ", "/proc/modules").CombinedOutput()
+	out, err := handle.executor.Command("cut", "-f1", "-d", " ", "/proc/modules").CombinedOutput()
 	if err != nil {
-		return false, err
+		return nil, err
 	}
 
 	mods := strings.Split(string(out), "\n")
+	return mods, nil
+}
+
+// CanUseIPVSProxier returns true if we can use the ipvs Proxier.
+// This is determined by checking if all the required kernel modules can be loaded. It may
+// return an error if it fails to get the kernel modules information without error, in which
+// case it will also return false.
+func CanUseIPVSProxier(handle KernelHandler, ipsetver IPSetVersioner) (bool, error) {
+	mods, err := handle.GetModules()
+	if err != nil {
+		return false, fmt.Errorf("error getting installed ipvs required kernel modules: %v", err)
+	}
 	wantModules := sets.NewString()
 	loadModules := sets.NewString()
 	wantModules.Insert(ipvsModules...)

pkg/proxy/ipvs/proxier_test.go

@@ -18,6 +18,7 @@ package ipvs
 
 import (
 	"bytes"
+	"fmt"
 	"net"
 	"reflect"
 	"testing"
@@ -87,6 +88,25 @@ func (fake *fakeHealthChecker) SyncEndpoints(newEndpoints map[types.NamespacedNa
 	return nil
 }
 
+// fakeKernelHandler implements KernelHandler.
+type fakeKernelHandler struct {
+	modules []string
+}
+
+func (fake *fakeKernelHandler) GetModules() ([]string, error) {
+	return fake.modules, nil
+}
+
+// fakeKernelHandler implements KernelHandler.
+type fakeIPSetVersioner struct {
+	version string
+	err     error
+}
+
+func (fake *fakeIPSetVersioner) GetVersion() (string, error) {
+	return fake.version, fake.err
+}
+
 func NewFakeProxier(ipt utiliptables.Interface, ipvs utilipvs.Interface, ipset utilipset.Interface, nodeIPs []net.IP) *Proxier {
 	fcmd := fakeexec.FakeCmd{
 		CombinedOutputScript: []fakeexec.FakeCombinedOutputAction{
@@ -180,6 +200,70 @@ func makeTestEndpoints(namespace, name string, eptFunc func(*api.Endpoints)) *ap
 	return ept
 }
 
+func TestCanUseIPVSProxier(t *testing.T) {
+	testCases := []struct {
+		mods         []string
+		kernelErr    error
+		ipsetVersion string
+		ipsetErr     error
+		ok           bool
+	}{
+		// case 0, kernel error
+		{
+			mods:         []string{"foo", "bar", "baz"},
+			kernelErr:    fmt.Errorf("oops"),
+			ipsetVersion: "0.0",
+			ok:           false,
+		},
+		// case 1, ipset error
+		{
+			mods:         []string{"foo", "bar", "baz"},
+			ipsetVersion: MinIPSetCheckVersion,
+			ipsetErr:     fmt.Errorf("oops"),
+			ok:           false,
+		},
+		// case 2, missing required kernel modules and ipset version too low
+		{
+			mods:         []string{"foo", "bar", "baz"},
+			ipsetVersion: "1.1",
+			ok:           false,
+		},
+		// case 3, missing required ip_vs_* kernel modules
+		{
+			mods:         []string{"ip_vs", "a", "bc", "def"},
+			ipsetVersion: MinIPSetCheckVersion,
+			ok:           false,
+		},
+		// case 4, ipset version too low
+		{
+			mods:         []string{"ip_vs", "ip_vs_rr", "ip_vs_wrr", "ip_vs_sh", "nf_conntrack_ipv4"},
+			ipsetVersion: "4.3.0",
+			ok:           false,
+		},
+		// case 5
+		{
+			mods:         []string{"ip_vs", "ip_vs_rr", "ip_vs_wrr", "ip_vs_sh", "nf_conntrack_ipv4"},
+			ipsetVersion: MinIPSetCheckVersion,
+			ok:           true,
+		},
+		// case 6
+		{
+			mods:         []string{"ip_vs", "ip_vs_rr", "ip_vs_wrr", "ip_vs_sh", "nf_conntrack_ipv4", "foo", "bar"},
+			ipsetVersion: "6.19",
+			ok:           true,
+		},
+	}
+
+	for i := range testCases {
+		handle := &fakeKernelHandler{modules: testCases[i].mods}
+		versioner := &fakeIPSetVersioner{version: testCases[i].ipsetVersion, err: testCases[i].ipsetErr}
+		ok, _ := CanUseIPVSProxier(handle, versioner)
+		if ok != testCases[i].ok {
+			t.Errorf("Case [%d], expect %v, got %v", i, testCases[i].ok, ok)
+		}
+	}
+}
+
 func TestNodePort(t *testing.T) {
 	ipt := iptablestest.NewFake()
 	ipvs := ipvstest.NewFake()