Add default batch scheduler argument (#2143)

* Add default batch scheduler argument

Signed-off-by: Jacob Salway <jacob.salway@gmail.com>

* Add helm unit test

Signed-off-by: Jacob Salway <jacob.salway@gmail.com>

---------

Signed-off-by: Jacob Salway <jacob.salway@gmail.com>

charts/spark-operator-chart/README.md

@@ -90,6 +90,7 @@ See [helm uninstall](https://helm.sh/docs/helm/helm_uninstall) for command docum
 | controller.uiIngress.enable | bool | `false` | Specifies whether to create ingress for Spark web UI. `controller.uiService.enable` must be `true` to enable ingress. |
 | controller.uiIngress.urlFormat | string | `""` | Ingress URL format. Required if `controller.uiIngress.enable` is true. |
 | controller.batchScheduler.enable | bool | `false` | Specifies whether to enable batch scheduler for spark jobs scheduling. If enabled, users can specify batch scheduler name in spark application. |
+| controller.batchScheduler.default | string | `""` | Default batch scheduler to be used if not specified by the user. If specified, this value must be either "volcano" or "yunikorn". Specifying any other value will cause the controller to error on startup. |
 | controller.serviceAccount.create | bool | `true` | Specifies whether to create a service account for the controller. |
 | controller.serviceAccount.name | string | `""` | Optional name for the controller service account. |
 | controller.serviceAccount.annotations | object | `{}` | Extra annotations for the controller service account. |

charts/spark-operator-chart/templates/controller/deployment.yaml

@@ -70,8 +70,9 @@ spec:
         - --ingress-url-format={{ . }}
         {{- end }}
         {{- end }}
-        {{- with .Values.controller.batchScheduler.enable }}
+        {{- if .Values.controller.batchScheduler.enable }}
         - --enable-batch-scheduler=true
+        - --default-batch-scheduler={{ .Values.controller.batchScheduler.default }}
         {{- end }}
         {{- if .Values.prometheus.metrics.enable }}
         - --enable-metrics=true

charts/spark-operator-chart/tests/controller/deployment_test.yaml

@@ -160,6 +160,17 @@ tests:
           path: spec.template.spec.containers[?(@.name=="spark-operator-controller")].args
           content: --enable-batch-scheduler=true
 
+  - it: Should contain `--default-batch-scheduler` arg if `controller.batchScheduler.default` is set
+    set:
+      controller:
+        batchScheduler:
+          enable: true
+          default: yunikorn
+    asserts:
+      - contains:
+          path: spec.template.spec.containers[?(@.name=="spark-operator-controller")].args
+          content: --default-batch-scheduler=yunikorn
+
   - it: Should contain `--enable-metrics` arg if `prometheus.metrics.enable` is set to `true`
     set:
       prometheus:

charts/spark-operator-chart/values.yaml

@@ -67,6 +67,10 @@ controller:
     # -- Specifies whether to enable batch scheduler for spark jobs scheduling.
     # If enabled, users can specify batch scheduler name in spark application.
     enable: false
+    # -- Default batch scheduler to be used if not specified by the user.
+    # If specified, this value must be either "volcano" or "yunikorn". Specifying any other
+    # value will cause the controller to error on startup.
+    default: ""
 
   serviceAccount:
     # -- Specifies whether to create a service account for the controller.

cmd/operator/controller/start.go

@@ -20,6 +20,7 @@ import (
 	"crypto/tls"
 	"flag"
 	"os"
+	"slices"
 	"time"
 
 	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
@@ -72,7 +73,8 @@ var (
 	cacheSyncTimeout  time.Duration
 
 	// Batch scheduler
-	enableBatchScheduler bool
+	enableBatchScheduler  bool
+	defaultBatchScheduler string
 
 	// Spark web UI service and ingress
 	enableUIService  bool
@@ -128,6 +130,8 @@ func NewStartCommand() *cobra.Command {
 	command.Flags().DurationVar(&cacheSyncTimeout, "cache-sync-timeout", 30*time.Second, "Informer cache sync timeout.")
 
 	command.Flags().BoolVar(&enableBatchScheduler, "enable-batch-scheduler", false, "Enable batch schedulers.")
+	command.Flags().StringVar(&defaultBatchScheduler, "default-batch-scheduler", "", "Default batch scheduler.")
+
 	command.Flags().BoolVar(&enableUIService, "enable-ui-service", true, "Enable Spark Web UI service.")
 	command.Flags().StringVar(&ingressClassName, "ingress-class-name", "", "Set ingressClassName for ingress resources created.")
 	command.Flags().StringVar(&ingressURLFormat, "ingress-url-format", "", "Ingress URL format.")
@@ -207,8 +211,14 @@ func start() {
 	var registry *scheduler.Registry
 	if enableBatchScheduler {
 		registry = scheduler.GetRegistry()
-		registry.Register(common.VolcanoSchedulerName, volcano.Factory)
-		registry.Register(yunikorn.SchedulerName, yunikorn.Factory)
+		_ = registry.Register(common.VolcanoSchedulerName, volcano.Factory)
+		_ = registry.Register(yunikorn.SchedulerName, yunikorn.Factory)
+
+		schedulerNames := registry.GetRegisteredSchedulerNames()
+		if defaultBatchScheduler != "" && !slices.Contains(schedulerNames, defaultBatchScheduler) {
+			logger.Error(nil, "Failed to find default batch scheduler in registered schedulers")
+			os.Exit(1)
+		}
 	}
 
 	// Setup controller for SparkApplication.
@@ -348,6 +358,7 @@ func newSparkApplicationReconcilerOptions() sparkapplication.Options {
 		EnableUIService:         enableUIService,
 		IngressClassName:        ingressClassName,
 		IngressURLFormat:        ingressURLFormat,
+		DefaultBatchScheduler:   defaultBatchScheduler,
 		SparkApplicationMetrics: sparkApplicationMetrics,
 		SparkExecutorMetrics:    sparkExecutorMetrics,
 	}

internal/controller/sparkapplication/controller.go

@@ -54,10 +54,11 @@ var (
 
 // Options defines the options of the controller.
 type Options struct {
-	Namespaces       []string
-	EnableUIService  bool
-	IngressClassName string
-	IngressURLFormat string
+	Namespaces            []string
+	EnableUIService       bool
+	IngressClassName      string
+	IngressURLFormat      string
+	DefaultBatchScheduler string
 
 	SparkApplicationMetrics *metrics.SparkApplicationMetrics
 	SparkExecutorMetrics    *metrics.SparkExecutorMetrics
@@ -1184,14 +1185,24 @@ func (r *Reconciler) resetSparkApplicationStatus(app *v1beta2.SparkApplication)
 }
 
 func (r *Reconciler) shouldDoBatchScheduling(app *v1beta2.SparkApplication) (bool, scheduler.Interface) {
-	if r.registry == nil || app.Spec.BatchScheduler == nil || *app.Spec.BatchScheduler == "" {
+	// If batch scheduling isn't enabled
+	if r.registry == nil {
+		return false, nil
+	}
+
+	schedulerName := r.options.DefaultBatchScheduler
+	if app.Spec.BatchScheduler != nil && *app.Spec.BatchScheduler != "" {
+		schedulerName = *app.Spec.BatchScheduler
+	}
+
+	// If both the default and app batch scheduler are unspecified or empty
+	if schedulerName == "" {
 		return false, nil
 	}
 
 	var err error
 	var scheduler scheduler.Interface
 
-	schedulerName := *app.Spec.BatchScheduler
 	switch schedulerName {
 	case common.VolcanoSchedulerName:
 		config := &volcano.Config{