Doc behaviour of default and interruptible NodeSelector and Tolerations

go/tasks/plugins/k8s/spark/spark.go

@@ -240,7 +240,8 @@ func (sparkResourceHandler) BuildResource(ctx context.Context, taskCtx pluginsCo
 		j.Spec.MainClass = &sparkJob.MainClass
 	}
 
-	// Add Tolerations/NodeSelector to only Executor pods.
+	// Add Interruptible Tolerations/NodeSelector to only Executor pods.
+	// The Interruptible NodeSelector takes precedence over the DefaultNodeSelector
 	if taskCtx.TaskExecutionMetadata().IsInterruptible() {
 		j.Spec.Executor.Tolerations = append(j.Spec.Executor.Tolerations, config.GetK8sPluginConfig().InterruptibleTolerations...)
 		j.Spec.Executor.NodeSelector = config.GetK8sPluginConfig().InterruptibleNodeSelector

go/tasks/plugins/k8s/spark/spark_test.go

@@ -495,7 +495,10 @@ func TestBuildResourceSpark(t *testing.T) {
 	assert.Equal(t, defaultPodHostNetwork, *sparkApp.Spec.Executor.HostNetwork)
 	assert.Equal(t, defaultPodHostNetwork, *sparkApp.Spec.Driver.HostNetwork)
 
-	// Validate Interruptible Toleration and NodeSelector set for Executor but not Driver.
+	// Validate
+	// * Interruptible Toleration and NodeSelector set for Executor but not Driver.
+	// * Validate Default NodeSelector set for Driver but overwritten with Interruptible NodeSelector for Executor.
+	// * Default Tolerations set for both Driver and Executor.
 	assert.Equal(t, 1, len(sparkApp.Spec.Driver.Tolerations))
 	assert.Equal(t, 1, len(sparkApp.Spec.Driver.NodeSelector))
 	assert.Equal(t, defaultNodeSelector, sparkApp.Spec.Driver.NodeSelector)
@@ -589,6 +592,7 @@ func TestBuildResourceSpark(t *testing.T) {
 	assert.True(t, ok)
 
 	// Validate Interruptible Toleration and NodeSelector not set  for both Driver and Executors.
+	// Validate that the default Toleration and NodeSelector are set for both Driver and Executors.
 	assert.Equal(t, 1, len(sparkApp.Spec.Driver.Tolerations))
 	assert.Equal(t, 1, len(sparkApp.Spec.Driver.NodeSelector))
 	assert.Equal(t, defaultNodeSelector, sparkApp.Spec.Driver.NodeSelector)