[SPARK-43504][K8S] Mounts the hadoop config map on the executor pod

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/HadoopConfDriverFeatureStep.scala

@@ -104,6 +104,14 @@ private[spark] class HadoopConfDriverFeatureStep(conf: KubernetesConf)
     }
   }
 
+  override def getAdditionalPodSystemProperties(): Map[String, String] = {
+    if (hasHadoopConf) {
+      Map(HADOOP_CONFIG_MAP_NAME -> existingConfMap.getOrElse(newConfigMapName))
+    } else {
+      Map.empty
+    }
+  }
+
   override def getAdditionalKubernetesResources(): Seq[HasMetadata] = {
     if (confDir.isDefined) {
       val fileMap = confFiles.map { file =>

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/HadoopConfExecutorFeatureStep.scala

@@ -0,0 +1,63 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.deploy.k8s.features
+
+import io.fabric8.kubernetes.api.model.{ContainerBuilder, PodBuilder, VolumeBuilder}
+
+import org.apache.spark.deploy.k8s.{KubernetesConf, SparkPod}
+import org.apache.spark.deploy.k8s.Constants._
+
+/**
+ * Mounts the Hadoop configuration on the executor pod.
+ */
+private[spark] class HadoopConfExecutorFeatureStep(conf: KubernetesConf)
+  extends KubernetesFeatureConfigStep {
+
+  private val hadoopConfigMapName = conf.getOption(HADOOP_CONFIG_MAP_NAME)
+
+  override def configurePod(original: SparkPod): SparkPod = {
+    original.transform { case pod if hadoopConfigMapName.isDefined =>
+      val confVolume = new VolumeBuilder()
+        .withName(HADOOP_CONF_VOLUME)
+        .withNewConfigMap()
+          .withName(hadoopConfigMapName.get)
+          .endConfigMap()
+        .build()
+
+      val podWithConf = new PodBuilder(pod.pod)
+        .editSpec()
+          .addNewVolumeLike(confVolume)
+            .endVolume()
+          .endSpec()
+          .build()
+
+      val containerWithMount = new ContainerBuilder(pod.container)
+        .addNewVolumeMount()
+          .withName(HADOOP_CONF_VOLUME)
+          .withMountPath(HADOOP_CONF_DIR_PATH)
+          .endVolumeMount()
+        .addNewEnv()
+          .withName(ENV_HADOOP_CONF_DIR)
+          .withValue(HADOOP_CONF_DIR_PATH)
+          .endEnv()
+        .build()
+
+      SparkPod(podWithConf, containerWithMount)
+    }
+  }
+}

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesExecutorBuilder.scala

@@ -71,6 +71,7 @@ private[spark] class KubernetesExecutorBuilder {
       new MountSecretsFeatureStep(conf),
       new EnvSecretsFeatureStep(conf),
       new MountVolumesFeatureStep(conf),
+      new HadoopConfExecutorFeatureStep(conf),
       new LocalDirsFeatureStep(conf)) ++ userFeatures
 
     val spec = KubernetesExecutorSpec(

resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/features/HadoopConfExecutorFeatureStepSuite.scala

@@ -0,0 +1,82 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.deploy.k8s.features
+
+import java.io.File
+import java.nio.charset.StandardCharsets.UTF_8
+
+import com.google.common.io.Files
+
+import org.apache.spark.{SparkConf, SparkFunSuite}
+import org.apache.spark.deploy.k8s.{Constants, KubernetesTestConf, SecretVolumeUtils, SparkPod}
+import org.apache.spark.deploy.k8s.Constants._
+import org.apache.spark.deploy.k8s.features.KubernetesFeaturesTestUtils.containerHasEnvVar
+import org.apache.spark.util.{SparkConfWithEnv, Utils}
+
+class HadoopConfExecutorFeatureStepSuite extends SparkFunSuite  {
+  import SecretVolumeUtils._
+
+  test("SPARK-43504: mounts the hadoop config map on the executor pod") {
+    val confDir = Utils.createTempDir()
+    val confFiles = Set("core-site.xml", "hdfs-site.xml")
+
+    confFiles.foreach { f =>
+      Files.write("some data", new File(confDir, f), UTF_8)
+    }
+
+    Seq(
+      Map(ENV_HADOOP_CONF_DIR -> confDir.getAbsolutePath()),
+      Map.empty[String, String]).foreach { env =>
+      val hasHadoopConf = env.contains(ENV_HADOOP_CONF_DIR)
+
+      val driverSparkConf = new SparkConfWithEnv(env)
+      val executorSparkConf = new SparkConf(false)
+
+      val driverConf = KubernetesTestConf.createDriverConf(sparkConf = driverSparkConf)
+      val driverStep = new HadoopConfDriverFeatureStep(driverConf)
+
+      val additionalPodSystemProperties = driverStep.getAdditionalPodSystemProperties()
+      if (hasHadoopConf) {
+        assert(additionalPodSystemProperties.contains(Constants.HADOOP_CONFIG_MAP_NAME))
+        additionalPodSystemProperties.foreach { case (key, value) =>
+          executorSparkConf.set(key, value)
+        }
+      } else {
+        assert(additionalPodSystemProperties.isEmpty)
+      }
+
+      val executorConf = KubernetesTestConf.createExecutorConf(sparkConf = executorSparkConf)
+      val executorStep = new HadoopConfExecutorFeatureStep(executorConf)
+      val executorPod = executorStep.configurePod(SparkPod.initialPod())
+
+      checkPod(executorPod, hasHadoopConf)
+    }
+  }
+
+  private def checkPod(pod: SparkPod, hasHadoopConf: Boolean): Unit = {
+    if (hasHadoopConf) {
+      assert(podHasVolume(pod.pod, HADOOP_CONF_VOLUME))
+      assert(containerHasVolume(pod.container, HADOOP_CONF_VOLUME, HADOOP_CONF_DIR_PATH))
+      assert(containerHasEnvVar(pod.container, ENV_HADOOP_CONF_DIR))
+    } else {
+      assert(!podHasVolume(pod.pod, HADOOP_CONF_VOLUME))
+      assert(!containerHasVolume(pod.container, HADOOP_CONF_VOLUME, HADOOP_CONF_DIR_PATH))
+      assert(!containerHasEnvVar(pod.container, ENV_HADOOP_CONF_DIR))
+    }
+  }
+}