feat: add featuregate for ensureNodeClass (#900)

**Reason for Change**:
Not all node auto provisioner requires the NodeClass CRD. To minimize
the dependency, add the feature gate ensureNodeClass to skip auto
generate NodeClass unless it is needed.

The feature is false by default.

**Issue Fixed**:
#898

cmd/workspace/main.go

@@ -32,6 +32,7 @@ import (
 	"github.com/kaito-project/kaito/pkg/featuregates"
 	"github.com/kaito-project/kaito/pkg/k8sclient"
 	kaitoutils "github.com/kaito-project/kaito/pkg/utils"
+	"github.com/kaito-project/kaito/pkg/utils/consts"
 	"github.com/kaito-project/kaito/pkg/utils/nodeclaim"
 	"github.com/kaito-project/kaito/pkg/workspace/controllers"
 	"github.com/kaito-project/kaito/pkg/workspace/webhooks"
@@ -161,9 +162,11 @@ func main() {
 		exitWithErrorFunc()
 	}
 
-	err = nodeclaim.CheckNodeClass(ctx, kClient)
-	if err != nil {
-		exitWithErrorFunc()
+	if featuregates.FeatureGates[consts.FeatureFlagEnsureNodeClass] {
+		err := nodeclaim.CheckNodeClass(ctx, kClient)
+		if err != nil {
+			exitWithErrorFunc()
+		}
 	}
 
 	klog.InfoS("starting manager")

pkg/featuregates/featuregates.go

@@ -13,9 +13,10 @@ import (
 )
 
 var (
-	// FeatureGates is a map that holds	the feature gates and their default values for Kaito.
+	// FeatureGates is a map that holds the feature gate names and their default values for Kaito.
 	FeatureGates = map[string]bool{
-		consts.FeatureFlagVLLM: true,
+		consts.FeatureFlagVLLM:            true,
+		consts.FeatureFlagEnsureNodeClass: false,
 		//	Add more feature gates here
 	}
 )

pkg/featuregates/featuregates_test.go

@@ -13,19 +13,22 @@ func TestParseFeatureGates(t *testing.T) {
 		name          string
 		featureGates  string
 		expectedError bool
-		expectedValue string
+		targetFeature string
+		expectedValue bool
 	}{
 		{
-			name:          "WithValidEnableFeatureGates",
+			name:          "WithValidEnableFeatureGates-vLLM",
 			featureGates:  "vLLM=true",
 			expectedError: false,
-			expectedValue: "true",
+			targetFeature: "vLLM",
+			expectedValue: true,
 		},
 		{
-			name:          "WithDuplicateFeatureGates",
+			name:          "WithDuplicateFeatureGates-vLLM",
 			featureGates:  "vLLM=false,vLLM=true",
 			expectedError: false,
-			expectedValue: "true", // Apply the last value.
+			targetFeature: "vLLM",
+			expectedValue: true, // Apply the last value.
 		},
 		{
 			name:          "WithInvalidFeatureGates",
@@ -38,10 +41,25 @@ func TestParseFeatureGates(t *testing.T) {
 			expectedError: true,
 		},
 		{
-			name:          "WithValidDisableFeatureGates",
+			name:          "WithValidDisableFeatureGates-vLLM",
 			featureGates:  "vLLM=false",
 			expectedError: false,
-			expectedValue: "false",
+			targetFeature: "vLLM",
+			expectedValue: false,
+		},
+		{
+			name:          "WithValidEnableFeatureGates-ensureNodeClass",
+			featureGates:  "ensureNodeClass=true",
+			expectedError: false,
+			targetFeature: "ensureNodeClass",
+			expectedValue: true,
+		},
+		{
+			name:          "WithValidDisableFeatureGates-ensureNodeClass",
+			featureGates:  "ensureNodeClass=false",
+			expectedError: false,
+			targetFeature: "ensureNodeClass",
+			expectedValue: false,
 		},
 		{
 			name:          "WithEmptyFeatureGates",
@@ -57,6 +75,9 @@ func TestParseFeatureGates(t *testing.T) {
 				assert.Check(t, err != nil, "expected error but got nil")
 			} else {
 				assert.NilError(t, err)
+				if tt.targetFeature != "" && FeatureGates[tt.targetFeature] != tt.expectedValue {
+					t.Errorf("feature gate test %s fails", tt.name)
+				}
 			}
 		})
 	}

pkg/utils/consts/consts.go

@@ -20,7 +20,8 @@ const (
 	NvidiaGPU                     = "nvidia.com/gpu"
 
 	// Feature flags
-	FeatureFlagVLLM = "vLLM"
+	FeatureFlagVLLM            = "vLLM"
+	FeatureFlagEnsureNodeClass = "ensureNodeClass"
 
 	// Nodeclaim related consts
 	KaitoNodePoolName             = "kaito"