[SPARK-24683][K8S] Fix k8s no resource on palantir/master (apache#387)

* [SPARK-24683][K8S] Add main class if no resource is provided for k8s.

* Add integration test.

Author: mccheah

core/src/main/scala/org/apache/spark/deploy/SparkSubmit.scala

@@ -702,6 +702,8 @@ private[spark] class SparkSubmit extends Logging {
           childArgs ++= Array("--primary-java-resource", args.primaryResource)
           childArgs ++= Array("--main-class", args.mainClass)
         }
+      } else {
+        childArgs ++= Array("--main-class", args.mainClass)
       }
       if (args.childArgs != null) {
         args.childArgs.foreach { arg =>

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/KubernetesDriverBuilder.scala

@@ -68,7 +68,8 @@ private[spark] class KubernetesDriverBuilder(
         case JavaMainAppResource(_) =>
           provideJavaStep(kubernetesConf)
         case PythonMainAppResource(_) =>
-          providePythonStep(kubernetesConf)}.getOrElse(provideJavaStep(kubernetesConf))
+          providePythonStep(kubernetesConf)}
+      .getOrElse(provideJavaStep(kubernetesConf))
 
     val localFiles = KubernetesUtils.submitterLocalFiles(kubernetesConf.sparkFiles)
       .map(new File(_))

resource-managers/kubernetes/integration-tests/src/test/scala/org/apache/spark/deploy/k8s/integrationtest/KubernetesSuite.scala

@@ -21,17 +21,17 @@ import java.nio.file.{Path, Paths}
 import java.util.UUID
 import java.util.regex.Pattern
 
-import scala.collection.JavaConverters._
-
 import com.google.common.io.PatternFilenameFilter
 import io.fabric8.kubernetes.api.model.{Container, Pod}
 import org.scalatest.{BeforeAndAfter, BeforeAndAfterAll}
 import org.scalatest.concurrent.{Eventually, PatienceConfiguration}
 import org.scalatest.time.{Minutes, Seconds, Span}
+import scala.collection.JavaConverters._
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.deploy.k8s.integrationtest.backend.{IntegrationTestBackend, IntegrationTestBackendFactory}
 import org.apache.spark.deploy.k8s.integrationtest.config._
+import org.apache.spark.launcher.SparkLauncher
 
 private[spark] class KubernetesSuite extends SparkFunSuite
   with BeforeAndAfterAll with BeforeAndAfter {
@@ -109,6 +109,12 @@ private[spark] class KubernetesSuite extends SparkFunSuite
     runSparkPiAndVerifyCompletion()
   }
 
+  test("Use SparkLauncher.NO_RESOURCE") {
+    sparkAppConf.setJars(Seq(containerLocalSparkDistroExamplesJar))
+    runSparkPiAndVerifyCompletion(
+      appResource = SparkLauncher.NO_RESOURCE)
+  }
+
   test("Run SparkPi with a master URL without a scheme.") {
     val url = kubernetesTestComponents.kubernetesClient.getMasterUrl
     val k8sMasterUrl = if (url.getPort < 0) {