feat: add Ethtool Config to CustomLinuxOSConfig

aks-node-controller/parser/helper.go

@@ -810,3 +810,18 @@ func getLocalDnsMemoryLimitInMb(aksnodeconfig *aksnodeconfigv1.Configuration) st
 }
 
 // ---------------------- End of localdns related helper code ----------------------//
+
+// ---------------------- Start of Ethtool Config related helper code ----------------------//
+
+func getEthtoolContents(ethtool_config *aksnodeconfigv1.EthtoolConfig) string {
+	if ethtool_config == nil || ethtool_config.GetRxBufferSize() <= 0 {
+		return ""
+	}
+
+	m := make(map[string]interface{})
+	m["rx"] = ethtool_config.GetRxBufferSize()
+
+	return base64.StdEncoding.EncodeToString([]byte(createSortedKeyValuePairs(m, "\n")))
+}
+
+// ---------------------- End of Ethtool Config related helper code ----------------------//

aks-node-controller/parser/helper_test.go

@@ -20,6 +20,7 @@ import (
 	_ "embed"
 	"encoding/base64"
 	"encoding/json"
+	"fmt"
 	"reflect"
 	"regexp"
 	"strings"
@@ -199,6 +200,131 @@ net.ipv4.tcp_retries2=8`)),
 	}
 }
 
+func Test_getEthtoolContents(t *testing.T) {
+	// Helper function to create base64 encoded rx value.
+	encodeRxValue := func(value int32) string {
+		return base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("rx=%d", value)))
+	}
+
+	type args struct {
+		e *aksnodeconfigv1.EthtoolConfig
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "Nil EthtoolConfig - returns empty string",
+			args: args{
+				e: nil,
+			},
+			want: "",
+		},
+		{
+			name: "Empty EthtoolConfig - returns empty string",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{},
+			},
+			want: "",
+		},
+		{
+			name: "Zero RxBufferSize pointer - returns empty string",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(0)),
+				},
+			},
+			want: "",
+		},
+		{
+			name: "Negative RxBufferSize - returns empty string",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(-1)),
+				},
+			},
+			want: "",
+		},
+		{
+			name: "Minimum positive value",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(1)),
+				},
+			},
+			want: encodeRxValue(1),
+		},
+		{
+			name: "Very small custom value",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(256)),
+				},
+			},
+			want: encodeRxValue(256),
+		},
+		{
+			name: "Custom RxBufferSize 512",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(512)),
+				},
+			},
+			want: encodeRxValue(512),
+		},
+		{
+			name: "Custom RxBufferSize 1024",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(1024)),
+				},
+			},
+			want: encodeRxValue(1024),
+		},
+		{
+			name: "Custom RxBufferSize 2048",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(2048)),
+				},
+			},
+			want: encodeRxValue(2048),
+		},
+		{
+			name: "Custom RxBufferSize 4096",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(4096)),
+				},
+			},
+			want: encodeRxValue(4096),
+		},
+		{
+			name: "Very large custom value",
+			args: args{
+				e: &aksnodeconfigv1.EthtoolConfig{
+					RxBufferSize: to.Ptr(int32(8192)),
+				},
+			},
+			want: encodeRxValue(8192),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := getEthtoolContents(tt.args.e)
+			if got != tt.want {
+				// Decode both values for better error reporting
+				gotDecoded, _ := base64.StdEncoding.DecodeString(got)
+				wantDecoded, _ := base64.StdEncoding.DecodeString(tt.want)
+				t.Errorf("getEthtoolContents() = %v (decoded: %s), want %v (decoded: %s)",
+					got, gotDecoded, tt.want, wantDecoded)
+			}
+		})
+	}
+}
+
 func Test_getUlimitContent(t *testing.T) {
 	type args struct {
 		u *aksnodeconfigv1.UlimitConfig

aks-node-controller/parser/parser.go

@@ -177,6 +177,7 @@ func getCSEEnv(config *aksnodeconfigv1.Configuration) map[string]string {
 		"SERVICE_ACCOUNT_IMAGE_PULL_DEFAULT_CLIENT_ID":       config.GetServiceAccountImagePullProfile().GetDefaultClientId(),
 		"SERVICE_ACCOUNT_IMAGE_PULL_DEFAULT_TENANT_ID":       config.GetServiceAccountImagePullProfile().GetDefaultTenantId(),
 		"IDENTITY_BINDINGS_LOCAL_AUTHORITY_SNI":              config.GetServiceAccountImagePullProfile().GetLocalAuthoritySni(),
+		"ETHTOOL_CONTENT":                                    fmt.Sprintf("%v", getEthtoolContents(config.GetCustomLinuxOsConfig().GetEthtoolConfig())),
 	}
 
 	for i, cert := range config.CustomCaCerts {

aks-node-controller/parser/parser_test.go

@@ -195,6 +195,62 @@ oom_score = -999
 				assert.Equal(t, "true", vars["NEEDS_CGROUPV2"])
 			},
 		},
+		{
+			name:       "AKSUbuntu2204 with custom ethtool config",
+			folder:     "AKSUbuntu2204+CustomEthtoolConfig",
+			k8sVersion: "1.24.2",
+			aksNodeConfigUpdator: func(aksNodeConfig *aksnodeconfigv1.Configuration) {
+				aksNodeConfig.CustomLinuxOsConfig = &aksnodeconfigv1.CustomLinuxOsConfig{
+					EthtoolConfig: &aksnodeconfigv1.EthtoolConfig{
+						RxBufferSize: to.Ptr(int32(4096)),
+					},
+				}
+			},
+			validator: func(cmd *exec.Cmd) {
+				vars := environToMap(cmd.Env)
+				ethtoolContent, err := getBase64DecodedValue([]byte(vars["ETHTOOL_CONTENT"]))
+				require.NoError(t, err)
+				assert.Equal(t, "rx=4096", ethtoolContent)
+			},
+		},
+		{
+			name:       "AKSUbuntu2204 with default ethtool config (no defaults set)",
+			folder:     "AKSUbuntu2204+DefaultEthtoolConfig",
+			k8sVersion: "1.24.2",
+			aksNodeConfigUpdator: func(aksNodeConfig *aksnodeconfigv1.Configuration) {
+				aksNodeConfig.CustomLinuxOsConfig = &aksnodeconfigv1.CustomLinuxOsConfig{
+					EthtoolConfig: &aksnodeconfigv1.EthtoolConfig{
+						// No RxBufferSize set, should return empty string.
+					},
+				}
+			},
+			validator: func(cmd *exec.Cmd) {
+				vars := environToMap(cmd.Env)
+				ethtoolContent, err := getBase64DecodedValue([]byte(vars["ETHTOOL_CONTENT"]))
+				require.NoError(t, err)
+				// Should return empty string when no value is set.
+				assert.Equal(t, "", ethtoolContent)
+			},
+		},
+		{
+			name:       "AKSUbuntu2204 with zero ethtool buffer (returns empty)",
+			folder:     "AKSUbuntu2204+ZeroEthtoolConfig",
+			k8sVersion: "1.24.2",
+			aksNodeConfigUpdator: func(aksNodeConfig *aksnodeconfigv1.Configuration) {
+				aksNodeConfig.CustomLinuxOsConfig = &aksnodeconfigv1.CustomLinuxOsConfig{
+					EthtoolConfig: &aksnodeconfigv1.EthtoolConfig{
+						RxBufferSize: to.Ptr(int32(0)), // Zero should return empty string.
+					},
+				}
+			},
+			validator: func(cmd *exec.Cmd) {
+				vars := environToMap(cmd.Env)
+				ethtoolContent, err := getBase64DecodedValue([]byte(vars["ETHTOOL_CONTENT"]))
+				require.NoError(t, err)
+				// Zero value should return empty string.
+				assert.Equal(t, "", ethtoolContent)
+			},
+		},
 	}
 
 	for _, tt := range tests {
@@ -387,6 +443,10 @@ func TestAKSNodeConfigCompatibilityFromJsonToCSECommand(t *testing.T) {
 				assert.Equal(t, "", vars["SECURE_TLS_BOOTSTRAPPING_AAD_RESOURCE"])
 				assert.Equal(t, "", vars["SECURE_TLS_BOOTSTRAPPING_USER_ASSIGNED_IDENTITY_ID"])
 				assert.Equal(t, "", vars["CUSTOM_SECURE_TLS_BOOTSTRAPPING_CLIENT_URL"])
+				ethtoolContent, err := getBase64DecodedValue([]byte(vars["ETHTOOL_CONTENT"]))
+				require.NoError(t, err)
+				// With empty config, no default should be set, so ethtool content should be empty.
+				assert.Equal(t, "", ethtoolContent)
 			},
 		},
 	}