Add optional Hadoop 2.2 settings in sbt build.

If the Hadoop used is version 2.2 or derived from it, then Spark
will be compiled against protobuf-2.5 and a protobuf-2.5 version of
Akka 2.0.5.

project/SparkBuild.scala

@@ -30,6 +30,10 @@ object SparkBuild extends Build {
   val DEFAULT_HADOOP_VERSION = "1.0.4"
   val DEFAULT_YARN = false
 
+  // Whether the Hadoop version to build against is 2.2.x, or a variant of it. This can be set
+  // through the SPARK_IS_NEW_YARN environment variable.
+  val DEFAULT_IS_NEW_YARN = false
+
   // HBase version; set as appropriate.
   val HBASE_VERSION = "0.94.6"
 
@@ -55,8 +59,6 @@ object SparkBuild extends Build {
 
   lazy val mllib = Project("mllib", file("mllib"), settings = mllibSettings) dependsOn(core)
 
-  lazy val yarn = Project("yarn", file("yarn"), settings = yarnSettings) dependsOn(core)
-
   lazy val assemblyProj = Project("assembly", file("assembly"), settings = assemblyProjSettings)
     .dependsOn(core, bagel, mllib, repl, streaming) dependsOn(maybeYarn: _*)
 
@@ -68,14 +70,26 @@ object SparkBuild extends Build {
 
   // Allows build configuration to be set through environment variables
   lazy val hadoopVersion = scala.util.Properties.envOrElse("SPARK_HADOOP_VERSION", DEFAULT_HADOOP_VERSION)
+  lazy val isNewYarn = scala.util.Properties.envOrNone("SPARK_IS_NEW_YARN") match {
+    case None => {
+      val isNewHadoopVersion = "2.[2-9]*".r.findFirstIn(hadoopVersion).isDefined
+      (isNewHadoopVersion|| DEFAULT_IS_NEW_YARN)
+    }
+    case Some(v) => v.toBoolean
+  }
   lazy val isYarnEnabled = scala.util.Properties.envOrNone("SPARK_YARN") match {
     case None => DEFAULT_YARN
     case Some(v) => v.toBoolean
   }
 
+  // Build against a protobuf-2.5 compatible Akka if Hadoop 2 is used.
+  lazy val protobufVersion = if (isNewYarn) "2.5.0" else "2.4.1"
+  lazy val akkaVersion = if (isNewYarn) "2.0.5-protobuf-2.5" else "2.0.5"
+
   // Conditionally include the yarn sub-project
-  lazy val maybeYarn = if(isYarnEnabled) Seq[ClasspathDependency](yarn) else Seq[ClasspathDependency]()
-  lazy val maybeYarnRef = if(isYarnEnabled) Seq[ProjectReference](yarn) else Seq[ProjectReference]()
+  lazy val yarn = Project("yarn", file(if (isNewYarn) "new-yarn" else "yarn"), settings = yarnSettings) dependsOn(core)
+  lazy val maybeYarn = if (isYarnEnabled) Seq[ClasspathDependency](yarn) else Seq[ClasspathDependency]()
+  lazy val maybeYarnRef = if (isYarnEnabled) Seq[ProjectReference](yarn) else Seq[ProjectReference]()
 
   // Everything except assembly, tools and examples belong to packageProjects
   lazy val packageProjects = Seq[ProjectReference](core, repl, bagel, streaming, mllib) ++ maybeYarnRef
@@ -211,10 +225,10 @@ object SparkBuild extends Build {
       "com.ning" % "compress-lzf" % "0.8.4",
       "org.xerial.snappy" % "snappy-java" % "1.0.5",
       "org.ow2.asm" % "asm" % "4.0",
-      "com.google.protobuf" % "protobuf-java" % "2.4.1",
-      "com.typesafe.akka" % "akka-actor" % "2.0.5" excludeAll(excludeNetty),
-      "com.typesafe.akka" % "akka-remote" % "2.0.5" excludeAll(excludeNetty),
-      "com.typesafe.akka" % "akka-slf4j" % "2.0.5" excludeAll(excludeNetty),
+      "com.google.protobuf" % "protobuf-java" % protobufVersion,
+      "com.typesafe.akka" % "akka-actor" % akkaVersion excludeAll(excludeNetty),
+      "com.typesafe.akka" % "akka-remote" % akkaVersion excludeAll(excludeNetty),
+      "com.typesafe.akka" % "akka-slf4j" % akkaVersion excludeAll(excludeNetty),
       "it.unimi.dsi" % "fastutil" % "6.4.4",
       "colt" % "colt" % "1.2.0",
       "net.liftweb" % "lift-json_2.9.2" % "2.5",
@@ -289,7 +303,7 @@ object SparkBuild extends Build {
       "org.eclipse.paho" % "mqtt-client" % "0.4.0",
       "org.apache.flume" % "flume-ng-sdk" % "1.2.0" % "compile" excludeAll(excludeNetty, excludeSnappy),
       "org.twitter4j" % "twitter4j-stream" % "3.0.3" excludeAll(excludeNetty),
-      "com.typesafe.akka" % "akka-zeromq" % "2.0.5" excludeAll(excludeNetty),
+      "com.typesafe.akka" % "akka-zeromq" % akkaVersion excludeAll(excludeNetty),
       "org.apache.kafka" % "kafka_2.9.2" % "0.8.0-beta1"
         exclude("com.sun.jdmk", "jmxtools")
         exclude("com.sun.jmx", "jmxri")