SPARK-1639. Tidy up some Spark on YARN code

This contains a bunch of small tidyings of the Spark on YARN code.

I focused on the yarn stable code.  @tgravescs, let me know if you'd like me to make these for the alpha code as well.

Author: Sandy Ryza <sandy@cloudera.com>

Closes #561 from sryza/sandy-spark-1639 and squashes the following commits:

72b6a02 [Sandy Ryza] Fix comment and set name on driver thread
c2190b2 [Sandy Ryza] SPARK-1639. Tidy up some Spark on YARN code

3 files changed, 38 insertions, 38 deletions

diff --git a/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ClientBase.scala b/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ClientBase.scala
index 801e8b3815..29a35680c0 100644
--- a/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ClientBase.scala
+++ b/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ClientBase.scala
@@ -19,7 +19,6 @@ package org.apache.spark.deploy.yarn
 
 import java.io.File
 import java.net.{InetAddress, UnknownHostException, URI, URISyntaxException}
-import java.nio.ByteBuffer
 
 import scala.collection.JavaConversions._
 import scala.collection.mutable.{HashMap, ListBuffer, Map}
@@ -37,7 +36,7 @@ import org.apache.hadoop.yarn.api.ApplicationConstants.Environment
 import org.apache.hadoop.yarn.api.protocolrecords._
 import org.apache.hadoop.yarn.api.records._
 import org.apache.hadoop.yarn.conf.YarnConfiguration
-import org.apache.hadoop.yarn.util.{Apps, Records}
+import org.apache.hadoop.yarn.util.Records
 import org.apache.spark.{Logging, SparkConf, SparkContext}
 
 /**
@@ -169,14 +168,13 @@ trait ClientBase extends Logging {
     destPath
   }
 
-  def qualifyForLocal(localURI: URI): Path = {
+  private def qualifyForLocal(localURI: URI): Path = {
     var qualifiedURI = localURI
-    // If not specified assume these are in the local filesystem to keep behavior like Hadoop
+    // If not specified, assume these are in the local filesystem to keep behavior like Hadoop
     if (qualifiedURI.getScheme() == null) {
       qualifiedURI = new URI(FileSystem.getLocal(conf).makeQualified(new Path(qualifiedURI)).toString)
     }
-    val qualPath = new Path(qualifiedURI)
-    qualPath
+    new Path(qualifiedURI)
   }
 
   def prepareLocalResources(appStagingDir: String): HashMap[String, LocalResource] = {
@@ -305,13 +303,13 @@ trait ClientBase extends Logging {
 
     val amMemory = calculateAMMemory(newApp)
 
-    val JAVA_OPTS = ListBuffer[String]()
+    val javaOpts = ListBuffer[String]()
 
     // Add Xmx for AM memory
-    JAVA_OPTS += "-Xmx" + amMemory + "m"
+    javaOpts += "-Xmx" + amMemory + "m"
 
     val tmpDir = new Path(Environment.PWD.$(), YarnConfiguration.DEFAULT_CONTAINER_TEMP_DIR)
-    JAVA_OPTS += "-Djava.io.tmpdir=" + tmpDir
+    javaOpts += "-Djava.io.tmpdir=" + tmpDir
 
     // TODO: Remove once cpuset version is pushed out.
     // The context is, default gc for server class machines ends up using all cores to do gc -
@@ -325,11 +323,11 @@ trait ClientBase extends Logging {
     if (useConcurrentAndIncrementalGC) {
       // In our expts, using (default) throughput collector has severe perf ramifications in
       // multi-tenant machines
-      JAVA_OPTS += "-XX:+UseConcMarkSweepGC"
-      JAVA_OPTS += "-XX:+CMSIncrementalMode"
-      JAVA_OPTS += "-XX:+CMSIncrementalPacing"
-      JAVA_OPTS += "-XX:CMSIncrementalDutyCycleMin=0"
-      JAVA_OPTS += "-XX:CMSIncrementalDutyCycle=10"
+      javaOpts += "-XX:+UseConcMarkSweepGC"
+      javaOpts += "-XX:+CMSIncrementalMode"
+      javaOpts += "-XX:+CMSIncrementalPacing"
+      javaOpts += "-XX:CMSIncrementalDutyCycleMin=0"
+      javaOpts += "-XX:CMSIncrementalDutyCycle=10"
     }
 
     // SPARK_JAVA_OPTS is deprecated, but for backwards compatibility:
@@ -344,22 +342,22 @@ trait ClientBase extends Logging {
       // If we are being launched in client mode, forward the spark-conf options
       // onto the executor launcher
       for ((k, v) <- sparkConf.getAll) {
-        JAVA_OPTS += "-D" + k + "=" + "\\\"" + v + "\\\""
+        javaOpts += "-D" + k + "=" + "\\\"" + v + "\\\""
       }
     } else {
       // If we are being launched in standalone mode, capture and forward any spark
       // system properties (e.g. set by spark-class).
       for ((k, v) <- sys.props.filterKeys(_.startsWith("spark"))) {
-        JAVA_OPTS += "-D" + k + "=" + "\\\"" + v + "\\\""
+        javaOpts += "-D" + k + "=" + "\\\"" + v + "\\\""
       }
-      sys.props.get("spark.driver.extraJavaOptions").foreach(opts => JAVA_OPTS += opts)
-      sys.props.get("spark.driver.libraryPath").foreach(p => JAVA_OPTS += s"-Djava.library.path=$p")
+      sys.props.get("spark.driver.extraJavaOptions").foreach(opts => javaOpts += opts)
+      sys.props.get("spark.driver.libraryPath").foreach(p => javaOpts += s"-Djava.library.path=$p")
     }
-    JAVA_OPTS += ClientBase.getLog4jConfiguration(localResources)
+    javaOpts += ClientBase.getLog4jConfiguration(localResources)
 
     // Command for the ApplicationMaster
     val commands = Seq(Environment.JAVA_HOME.$() + "/bin/java", "-server") ++
-      JAVA_OPTS ++
+      javaOpts ++
       Seq(args.amClass, "--class", args.userClass, "--jar ", args.userJar,
         userArgsToString(args),
         "--executor-memory", args.executorMemory.toString,
diff --git a/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ExecutorRunnableUtil.scala b/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ExecutorRunnableUtil.scala
index 32f8861dc9..43dbb2464f 100644
--- a/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ExecutorRunnableUtil.scala
+++ b/yarn/common/src/main/scala/org/apache/spark/deploy/yarn/ExecutorRunnableUtil.scala
@@ -28,7 +28,7 @@ import org.apache.hadoop.yarn.api._
 import org.apache.hadoop.yarn.api.ApplicationConstants.Environment
 import org.apache.hadoop.yarn.api.records._
 import org.apache.hadoop.yarn.conf.YarnConfiguration
-import org.apache.hadoop.yarn.util.{Apps, ConverterUtils, Records}
+import org.apache.hadoop.yarn.util.{ConverterUtils, Records}
 
 import org.apache.spark.{Logging, SparkConf}
 
@@ -46,19 +46,19 @@ trait ExecutorRunnableUtil extends Logging {
       executorCores: Int,
       localResources: HashMap[String, LocalResource]): List[String] = {
     // Extra options for the JVM
-    val JAVA_OPTS = ListBuffer[String]()
+    val javaOpts = ListBuffer[String]()
     // Set the JVM memory
     val executorMemoryString = executorMemory + "m"
-    JAVA_OPTS += "-Xms" + executorMemoryString + " -Xmx" + executorMemoryString + " "
+    javaOpts += "-Xms" + executorMemoryString + " -Xmx" + executorMemoryString + " "
 
     // Set extra Java options for the executor, if defined
     sys.props.get("spark.executor.extraJavaOptions").foreach { opts =>
-      JAVA_OPTS += opts
+      javaOpts += opts
     }
 
-    JAVA_OPTS += "-Djava.io.tmpdir=" +
+    javaOpts += "-Djava.io.tmpdir=" +
       new Path(Environment.PWD.$(), YarnConfiguration.DEFAULT_CONTAINER_TEMP_DIR)
-    JAVA_OPTS += ClientBase.getLog4jConfiguration(localResources)
+    javaOpts += ClientBase.getLog4jConfiguration(localResources)
 
     // Certain configs need to be passed here because they are needed before the Executor
     // registers with the Scheduler and transfers the spark configs. Since the Executor backend
@@ -66,10 +66,10 @@ trait ExecutorRunnableUtil extends Logging {
     // authentication settings.
     sparkConf.getAll.
       filter { case (k, v) => k.startsWith("spark.auth") || k.startsWith("spark.akka") }.
-      foreach { case (k, v) => JAVA_OPTS += "-D" + k + "=" + "\\\"" + v + "\\\"" }
+      foreach { case (k, v) => javaOpts += "-D" + k + "=" + "\\\"" + v + "\\\"" }
 
     sparkConf.getAkkaConf.
-      foreach { case (k, v) => JAVA_OPTS += "-D" + k + "=" + "\\\"" + v + "\\\"" }
+      foreach { case (k, v) => javaOpts += "-D" + k + "=" + "\\\"" + v + "\\\"" }
 
     // Commenting it out for now - so that people can refer to the properties if required. Remove
     // it once cpuset version is pushed out.
@@ -88,11 +88,11 @@ trait ExecutorRunnableUtil extends Logging {
           // multi-tennent machines
           // The options are based on
           // http://www.oracle.com/technetwork/java/gc-tuning-5-138395.html#0.0.0.%20When%20to%20Use%20the%20Concurrent%20Low%20Pause%20Collector|outline
-          JAVA_OPTS += " -XX:+UseConcMarkSweepGC "
-          JAVA_OPTS += " -XX:+CMSIncrementalMode "
-          JAVA_OPTS += " -XX:+CMSIncrementalPacing "
-          JAVA_OPTS += " -XX:CMSIncrementalDutyCycleMin=0 "
-          JAVA_OPTS += " -XX:CMSIncrementalDutyCycle=10 "
+          javaOpts += " -XX:+UseConcMarkSweepGC "
+          javaOpts += " -XX:+CMSIncrementalMode "
+          javaOpts += " -XX:+CMSIncrementalPacing "
+          javaOpts += " -XX:CMSIncrementalDutyCycleMin=0 "
+          javaOpts += " -XX:CMSIncrementalDutyCycle=10 "
         }
     */
 
@@ -104,7 +104,7 @@ trait ExecutorRunnableUtil extends Logging {
       // TODO: If the OOM is not recoverable by rescheduling it on different node, then do
       // 'something' to fail job ... akin to blacklisting trackers in mapred ?
       "-XX:OnOutOfMemoryError='kill %p'") ++
-      JAVA_OPTS ++
+      javaOpts ++
       Seq("org.apache.spark.executor.CoarseGrainedExecutorBackend",
       masterAddress.toString,
       slaveId.toString,
diff --git a/yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClusterScheduler.scala b/yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClusterScheduler.scala
index a4638cc863..39cdd2e8a5 100644
--- a/yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClusterScheduler.scala
+++ b/yarn/common/src/main/scala/org/apache/spark/scheduler/cluster/YarnClusterScheduler.scala
@@ -33,10 +33,11 @@ private[spark] class YarnClusterScheduler(sc: SparkContext, conf: Configuration)
 
   def this(sc: SparkContext) = this(sc, new Configuration())
 
-  // Nothing else for now ... initialize application master : which needs sparkContext to determine how to allocate
-  // Note that only the first creation of SparkContext influences (and ideally, there must be only one SparkContext, right ?)
-  // Subsequent creations are ignored - since nodes are already allocated by then.
-
+  // Nothing else for now ... initialize application master : which needs a SparkContext to
+  // determine how to allocate.
+  // Note that only the first creation of a SparkContext influences (and ideally, there must be
+  // only one SparkContext, right ?). Subsequent creations are ignored since executors are already
+  // allocated by then.
 
   // By default, rack is unknown
   override def getRackForHost(hostPort: String): Option[String] = {
@@ -48,6 +49,7 @@ private[spark] class YarnClusterScheduler(sc: SparkContext, conf: Configuration)
   override def postStartHook() {
     val sparkContextInitialized = ApplicationMaster.sparkContextInitialized(sc)
     if (sparkContextInitialized){
+      ApplicationMaster.waitForInitialAllocations()
       // Wait for a few seconds for the slaves to bootstrap and register with master - best case attempt
       Thread.sleep(3000L)
     }