[SPARK-20085][MESOS] Configurable mesos labels for executors

## What changes were proposed in this pull request?

Add spark.mesos.task.labels configuration option to add mesos key:value labels to the executor.

 "k1:v1,k2:v2" as the format, colons separating key-value and commas to list out more than one.

Discussion of labels with mgummelt at #17404

## How was this patch tested?

Added unit tests to verify labels were added correctly, with incorrect labels being ignored and added a test to test the name of the executor.

Tested with: `./build/sbt -Pmesos mesos/test`

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: Kalvin Chau <kalvin.chau@viasat.com>

Closes #17413 from kalvinnchau/mesos-labels.

docs/running-on-mesos.md

@@ -367,6 +367,15 @@ See the [configuration page](configuration.html) for information on Spark config
     <pre>[host_path:]container_path[:ro|:rw]</pre>
   </td>
 </tr>
+<tr>
+  <td><code>spark.mesos.task.labels</code></td>
+  <td>(none)</td>
+  <td>
+    Set the Mesos labels to add to each task. Labels are free-form key-value pairs.
+    Key-value pairs should be separated by a colon, and commas used to list more than one.
+    Ex. key:value,key2:value2.
+  </td>
+</tr>
 <tr>
   <td><code>spark.mesos.executor.home</code></td>
   <td>driver side <code>SPARK_HOME</code></td>

resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosCoarseGrainedSchedulerBackend.scala

@@ -67,6 +67,8 @@ private[spark] class MesosCoarseGrainedSchedulerBackend(
 
   private val maxGpus = conf.getInt("spark.mesos.gpus.max", 0)
 
+  private val taskLabels = conf.get("spark.mesos.task.labels", "")
+
   private[this] val shutdownTimeoutMS =
     conf.getTimeAsMs("spark.mesos.coarse.shutdownTimeout", "10s")
       .ensuring(_ >= 0, "spark.mesos.coarse.shutdownTimeout must be >= 0")
@@ -408,6 +410,13 @@ private[spark] class MesosCoarseGrainedSchedulerBackend(
           taskBuilder.addAllResources(resourcesToUse.asJava)
           taskBuilder.setContainer(MesosSchedulerBackendUtil.containerInfo(sc.conf))
 
+          val labelsBuilder = taskBuilder.getLabelsBuilder
+          val labels = buildMesosLabels().asJava
+
+          labelsBuilder.addAllLabels(labels)
+
+          taskBuilder.setLabels(labelsBuilder)
+
           tasks(offer.getId) ::= taskBuilder.build()
           remainingResources(offerId) = resourcesLeft.asJava
           totalCoresAcquired += taskCPUs
@@ -422,6 +431,21 @@ private[spark] class MesosCoarseGrainedSchedulerBackend(
     tasks.toMap
   }
 
+  private def buildMesosLabels(): List[Label] = {
+   taskLabels.split(",").flatMap(label =>
+      label.split(":") match {
+        case Array(key, value) =>
+          Some(Label.newBuilder()
+            .setKey(key)
+            .setValue(value)
+            .build())
+        case _ =>
+          logWarning(s"Unable to parse $label into a key:value label for the task.")
+          None
+      }
+    ).toList
+  }
+
   /** Extracts task needed resources from a list of available resources. */
   private def partitionTaskResources(
       resources: JList[Resource],

resource-managers/mesos/src/test/scala/org/apache/spark/scheduler/cluster/mesos/MesosCoarseGrainedSchedulerBackendSuite.scala

@@ -475,6 +475,52 @@ class MesosCoarseGrainedSchedulerBackendSuite extends SparkFunSuite
     assert(launchedTasks.head.getName == "test-mesos-dynamic-alloc 0")
   }
 
+  test("mesos sets configurable labels on tasks") {
+    val taskLabelsString = "mesos:test,label:test"
+    setBackend(Map(
+      "spark.mesos.task.labels" -> taskLabelsString
+    ))
+
+    // Build up the labels
+    val taskLabels = Protos.Labels.newBuilder()
+      .addLabels(Protos.Label.newBuilder()
+        .setKey("mesos").setValue("test").build())
+      .addLabels(Protos.Label.newBuilder()
+        .setKey("label").setValue("test").build())
+      .build()
+
+    val offers = List(Resources(backend.executorMemory(sc), 1))
+    offerResources(offers)
+    val launchedTasks = verifyTaskLaunched(driver, "o1")
+
+    val labels = launchedTasks.head.getLabels
+
+    assert(launchedTasks.head.getLabels.equals(taskLabels))
+  }
+
+  test("mesos ignored invalid labels and sets configurable labels on tasks") {
+    val taskLabelsString = "mesos:test,label:test,incorrect:label:here"
+    setBackend(Map(
+      "spark.mesos.task.labels" -> taskLabelsString
+    ))
+
+    // Build up the labels
+    val taskLabels = Protos.Labels.newBuilder()
+      .addLabels(Protos.Label.newBuilder()
+        .setKey("mesos").setValue("test").build())
+      .addLabels(Protos.Label.newBuilder()
+        .setKey("label").setValue("test").build())
+      .build()
+
+    val offers = List(Resources(backend.executorMemory(sc), 1))
+    offerResources(offers)
+    val launchedTasks = verifyTaskLaunched(driver, "o1")
+
+    val labels = launchedTasks.head.getLabels
+
+    assert(launchedTasks.head.getLabels.equals(taskLabels))
+  }
+
   test("mesos supports spark.mesos.network.name") {
     setBackend(Map(
       "spark.mesos.network.name" -> "test-network-name"