ipvs: check for existence of scheduler module and fail if not found

Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>

cmd/kube-proxy/app/server_others_test.go

@@ -111,6 +111,7 @@ func Test_getProxyMode(t *testing.T) {
 			kernelVersion: "4.18",
 			ipsetVersion:  ipvs.MinIPSetCheckVersion,
 			expected:      proxyModeIPVS,
+			scheduler:     "rr",
 		},
 		{ // flag says ipvs, ipset version ok, kernel modules installed for linux kernel 4.19
 			flag:          "ipvs",
@@ -118,6 +119,7 @@ func Test_getProxyMode(t *testing.T) {
 			kernelVersion: "4.19",
 			ipsetVersion:  ipvs.MinIPSetCheckVersion,
 			expected:      proxyModeIPVS,
+			scheduler:     "rr",
 		},
 		{ // flag says ipvs, ipset version too low, fallback on iptables mode
 			flag:          "ipvs",
@@ -151,13 +153,14 @@ func Test_getProxyMode(t *testing.T) {
 			expected:      proxyModeIPVS,
 			scheduler:     "sed",
 		},
-		{ // flag says ipvs, ipset version ok, non-existent scheduler
+		{ // flag says ipvs, kernel modules not installed for sed scheduler, fallback to iptables
 			flag:          "ipvs",
-			kmods:         []string{"ip_vs", "ip_vs_rr", "ip_vs_wrr", "ip_vs_sh", "nf_conntrack", "ip_vs_sed"},
+			kmods:         []string{"ip_vs", "ip_vs_rr", "ip_vs_wrr", "ip_vs_sh", "nf_conntrack"},
 			kernelVersion: "4.19",
 			ipsetVersion:  ipvs.MinIPSetCheckVersion,
-			expected:      proxyModeIPVS,
+			expected:      proxyModeIPTables,
-			scheduler:     "foobar",
+			kernelCompat:  true,
+			scheduler:     "sed",
 		},
 	}
 	for i, c := range cases {
@@ -167,11 +170,7 @@ func Test_getProxyMode(t *testing.T) {
 			modules:       c.kmods,
 			kernelVersion: c.kernelVersion,
 		}
-		scheduler := cases[i].scheduler
+		canUseIPVS, _ := ipvs.CanUseIPVSProxier(khandler, ipsetver, cases[i].scheduler)
-		if scheduler == "" {
-			scheduler = "rr"
-		}
-		canUseIPVS, _ := ipvs.CanUseIPVSProxier(khandler, ipsetver, scheduler)
 		r := getProxyMode(c.flag, canUseIPVS, kcompater)
 		if r != c.expected {
 			t.Errorf("Case[%d] Expected %q, got %q", i, c.expected, r)

pkg/proxy/ipvs/proxier.go

@@ -711,10 +711,11 @@ func CanUseIPVSProxier(handle KernelHandler, ipsetver IPSetVersioner, scheduler
 	}
 	mods = utilipvs.GetRequiredIPVSModules(kernelVersion)
 	wantModules := sets.NewString()
-	schedulerMod, modNotFound := utilipvs.GetRequiredSchedulerModules(scheduler)
+	// We check for the existence of the scheduler mod and will trigger a missingMods error if not found
-	if modNotFound != nil {
+	if scheduler == "" {
-		klog.Error(modNotFound)
+		scheduler = DefaultScheduler
 	}
+	schedulerMod := "ip_vs_" + scheduler
 	mods = append(mods, schedulerMod)
 	wantModules.Insert(mods...)
 

pkg/proxy/ipvs/proxier_test.go

@@ -348,13 +348,13 @@ func TestCanUseIPVSProxier(t *testing.T) {
 			ipsetVersion:  MinIPSetCheckVersion,
 			ok:            true,
 		},
-		// case 10, non-existent scheduler, fallback to rr
+		// case 10, non-existent scheduler, error due to modules not existing
 		{
 			mods:          []string{"ip_vs", "ip_vs_rr", "ip_vs_wrr", "ip_vs_sh", "nf_conntrack", "ip_vs_dh"},
 			scheduler:     "foobar",
 			kernelVersion: "4.19",
 			ipsetVersion:  MinIPSetCheckVersion,
-			ok:            true,
+			ok:            false,
 		},
 	}
 

pkg/util/ipvs/ipvs.go

@@ -17,7 +17,6 @@ limitations under the License.
 package ipvs
 
 import (
-	"fmt"
 	"net"
 	"strconv"
 	"strings"
@@ -84,14 +83,6 @@ const (
 	KernelModuleIPVSWRR string = "ip_vs_wrr"
 	// KernelModuleIPVSSH is the kernel module "ip_vs_sh"
 	KernelModuleIPVSSH string = "ip_vs_sh"
-	// KernelModuleIPVSLC is the kernel module "ip_vs_lc"
-	KernelModuleIPVSLC string = "ip_vs_lc"
-	// KernelModuleIPVSNQ is the kernel module "ip_vs_nq"
-	KernelModuleIPVSNQ string = "ip_vs_nq"
-	// KernelModuleIPVSDH is the kernel module "ip_vs_dh"
-	KernelModuleIPVSDH string = "ip_vs_dh"
-	// KernelModuleIPVSSED is the kernel module "ip_vs_sed"
-	KernelModuleIPVSSED string = "ip_vs_sed"
 	// KernelModuleNfConntrackIPV4 is the module "nf_conntrack_ipv4"
 	KernelModuleNfConntrackIPV4 string = "nf_conntrack_ipv4"
 	// KernelModuleNfConntrack is the kernel module "nf_conntrack"
@@ -148,26 +139,3 @@ func GetRequiredIPVSModules(kernelVersion *version.Version) []string {
 func IsRsGracefulTerminationNeeded(proto string) bool {
 	return !strings.EqualFold(proto, "UDP") && !strings.EqualFold(proto, "SCTP")
 }
-
-// GetRequiredSchedulerModules returns the required ipvs scheduler module for configured scheduler
-func GetRequiredSchedulerModules(scheduler string) (string, error) {
-	switch s := scheduler; s {
-	case "rr":
-		return KernelModuleIPVSRR, nil
-	case "lc":
-		return KernelModuleIPVSLC, nil
-	case "nq":
-		return KernelModuleIPVSNQ, nil
-	case "dh":
-		return KernelModuleIPVSDH, nil
-	case "sh":
-		return KernelModuleIPVSSH, nil
-	case "sed":
-		return KernelModuleIPVSSED, nil
-	case "":
-		return KernelModuleIPVSRR, nil
-	default:
-		notFound := fmt.Errorf("ip_vs_%s is not a supported IPVS scheduler algorithm, falling back to round-robin", scheduler)
-		return KernelModuleIPVSRR, notFound
-	}
-}

pkg/util/ipvs/ipvs_test.go

@@ -17,7 +17,6 @@ limitations under the License.
 package ipvs
 
 import (
-	"fmt"
 	"net"
 	"reflect"
 	"sort"
@@ -414,51 +413,3 @@ func TestGetRequiredIPVSModules(t *testing.T) {
 		})
 	}
 }
-
-func TestGetRequiredSchedulerModules(t *testing.T) {
-	Tests := []struct {
-		name         string
-		scheduler    string
-		want         string
-		expectedErrs error
-	}{
-		{
-			name:         "scheduler explicitly set to  rr",
-			scheduler:    "rr",
-			want:         "ip_vs_rr",
-			expectedErrs: nil,
-		},
-		{
-			name:         "scheduler set to  nq",
-			scheduler:    "nq",
-			want:         "ip_vs_nq",
-			expectedErrs: nil,
-		},
-		{
-			name:         "unset scheduler",
-			scheduler:    "",
-			want:         "ip_vs_rr",
-			expectedErrs: nil,
-		},
-		{
-			name:         "invalid scheduler algorithm",
-			scheduler:    "foobar",
-			want:         "ip_vs_rr",
-			expectedErrs: fmt.Errorf("ip_vs_%s is not a supported IPVS scheduler algorithm, falling back to round-robin", "foobar"),
-		},
-	}
-
-	for _, test := range Tests {
-		t.Run(test.name, func(t *testing.T) {
-			got, err := GetRequiredSchedulerModules(test.scheduler)
-			if !reflect.DeepEqual(got, test.want) {
-				t.Fatalf("GetRequiredSchedulerModules() = testCase %v failed- expected: %s scheduler, but got: %s", test.name, test.want, got)
-			}
-			if err != nil {
-				if err.Error() != test.expectedErrs.Error() {
-					t.Fatalf("Expected error: %v, got: %v", test.expectedErrs, err.Error())
-				}
-			}
-		})
-	}
-}