refactor: move scheduler config to a utils/scheduler package`

- use default config as a fallback
Signed-off-by: vadasambar <surajrbanakar@gmail.com>

cluster-autoscaler/main.go

@@ -55,6 +55,7 @@ import (
 	"k8s.io/autoscaler/cluster-autoscaler/simulator/clustersnapshot"
 	"k8s.io/autoscaler/cluster-autoscaler/utils/errors"
 	kube_util "k8s.io/autoscaler/cluster-autoscaler/utils/kubernetes"
+	scheduler_util "k8s.io/autoscaler/cluster-autoscaler/utils/scheduler"
 	"k8s.io/autoscaler/cluster-autoscaler/utils/units"
 	"k8s.io/autoscaler/cluster-autoscaler/version"
 	kube_client "k8s.io/client-go/kubernetes"
@@ -67,9 +68,6 @@ import (
 	"k8s.io/component-base/config/options"
 	"k8s.io/component-base/metrics/legacyregistry"
 	"k8s.io/klog/v2"
-	schedconfig "k8s.io/kubernetes/pkg/scheduler/apis/config"
-	schedscheme "k8s.io/kubernetes/pkg/scheduler/apis/config/scheme"
-	schedvalidation "k8s.io/kubernetes/pkg/scheduler/apis/config/validation"
 )
 
 // MultiStringFlag is a flag for passing multiple parameters using same flag
@@ -256,7 +254,10 @@ func createAutoscalingOptions() config.AutoscalingOptions {
 		klog.Fatalf("Invalid configuration, could not use --max-drain-parallelism > 1 if --parallel-drain is false")
 	}
 
-	parsedSchedConfig := getSchedulerConfig(*schedulerConfig)
+	parsedSchedConfig, err := scheduler_util.GetSchedulerConfig(*schedulerConfig)
+	if err != nil {
+		klog.Fatalf("Failed to get scheduler config: %v", err)
+	}
 
 	return config.AutoscalingOptions{
 		NodeGroupDefaults: config.NodeGroupAutoscalingOptions{
@@ -376,36 +377,6 @@ func getKubeConfig() *rest.Config {
 	return kubeConfig
 }
 
-func getSchedulerConfig(path string) *schedconfig.KubeSchedulerConfiguration {
-	data, err := os.ReadFile(path)
-
-	defaultFallback := "(falling back to default scheduler config)"
-
-	if err != nil {
-		klog.Errorf("couldn't load scheduler config %s: %v", defaultFallback, err)
-		return &schedconfig.KubeSchedulerConfiguration{}
-	}
-
-	obj, gvk, err := schedscheme.Codecs.UniversalDecoder().Decode(data, nil, nil)
-	if err != nil {
-		klog.Errorf("couldn't decode scheduler config %s: %v", defaultFallback, err)
-		return &schedconfig.KubeSchedulerConfiguration{}
-	}
-
-	cfgObj, ok := obj.(*schedconfig.KubeSchedulerConfiguration)
-	if !ok {
-		klog.Errorf("couldn't decode as KubeSchedulerConfiguration, got %s %s", defaultFallback, gvk)
-		return &schedconfig.KubeSchedulerConfiguration{}
-	}
-
-	if err := schedvalidation.ValidateKubeSchedulerConfiguration(cfgObj); err != nil {
-		klog.Errorf("invalid KubeSchedulerConfiguration %s: %v", defaultFallback, err)
-		return &schedconfig.KubeSchedulerConfiguration{}
-	}
-
-	return cfgObj
-}
-
 func createKubeClient(kubeConfig *rest.Config) kube_client.Interface {
 	return kube_client.NewForConfigOrDie(kubeConfig)
 }

cluster-autoscaler/utils/scheduler/scheduler.go

@@ -18,11 +18,17 @@ package scheduler
 
 import (
 	"fmt"
+	"os"
 	"strings"
 
 	apiv1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/util/uuid"
+	"k8s.io/klog/v2"
+	schedconfig "k8s.io/kubernetes/pkg/scheduler/apis/config"
+	schedconfiglatest "k8s.io/kubernetes/pkg/scheduler/apis/config/latest"
+	schedscheme "k8s.io/kubernetes/pkg/scheduler/apis/config/scheme"
+	schedvalidation "k8s.io/kubernetes/pkg/scheduler/apis/config/validation"
 	schedulerframework "k8s.io/kubernetes/pkg/scheduler/framework"
 )
 
@@ -106,3 +112,38 @@ func ResourceToResourceList(r *schedulerframework.Resource) apiv1.ResourceList {
 	}
 	return result
 }
+
+// GetSchedulerConfig loads scheduler config from a path
+// (falls back to default config in case of error)
+func GetSchedulerConfig(path string) (*schedconfig.KubeSchedulerConfiguration, error) {
+	defaultFallbackMsg := "(falling back to default scheduler config)"
+	defaultFallback, err := schedconfiglatest.Default()
+	if err != nil {
+		return nil, fmt.Errorf("couldn't create scheduler config: %v", err)
+	}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		klog.Errorf("couldn't load scheduler config %s: %v", defaultFallbackMsg, err)
+		return defaultFallback, nil
+	}
+
+	obj, gvk, err := schedscheme.Codecs.UniversalDecoder().Decode(data, nil, nil)
+	if err != nil {
+		klog.Errorf("couldn't decode scheduler config %s: %v", defaultFallbackMsg, err)
+		return defaultFallback, nil
+	}
+
+	cfgObj, ok := obj.(*schedconfig.KubeSchedulerConfiguration)
+	if !ok {
+		klog.Errorf("couldn't decode as KubeSchedulerConfiguration, got %s %s", defaultFallbackMsg, gvk)
+		return defaultFallback, nil
+	}
+
+	if err := schedvalidation.ValidateKubeSchedulerConfiguration(cfgObj); err != nil {
+		klog.Errorf("invalid KubeSchedulerConfiguration %s: %v", defaultFallbackMsg, err)
+		return defaultFallback, nil
+	}
+
+	return cfgObj, nil
+}