在火花流中找不到KafkaUtils类

Question

我刚刚从星火流开始，我正在尝试构建一个示例应用程序来统计Kafka流中的单词。虽然它是用sbt package编译的，但当我运行它时，我得到了NoClassDefFoundError。这个post似乎也有同样的问题，但是解决方案是针对Maven的，而我还不能用sbt来再现它。

KafkaApp.scala

import org.apache.spark._
import org.apache.spark.streaming._
import org.apache.spark.streaming.kafka._

object KafkaApp {
  def main(args: Array[String]) {

    val conf = new SparkConf().setAppName("kafkaApp").setMaster("local[*]")
    val ssc = new StreamingContext(conf, Seconds(1))
    val kafkaParams = Map(
        "zookeeper.connect" -> "localhost:2181",
        "zookeeper.connection.timeout.ms" -> "10000",
        "group.id" -> "sparkGroup"
    )

    val topics = Map(
        "test" -> 1
    )

    // stream of (topic, ImpressionLog)
    val messages = KafkaUtils.createStream(ssc, kafkaParams, topics, storage.StorageLevel.MEMORY_AND_DISK)
    println(s"Number of words: %{messages.count()}")
  }
}

build.sbt

name := "Simple Project"

version := "1.1"

scalaVersion := "2.10.4"

libraryDependencies ++= Seq(
    "org.apache.spark" %% "spark-core" % "1.1.1",
    "org.apache.spark" %% "spark-streaming" % "1.1.1",
    "org.apache.spark" %% "spark-streaming-kafka" % "1.1.1"
)

resolvers += "Akka Repository" at "http://repo.akka.io/releases/"

我提交这份报告时：

bin/spark-submit \
  --class "KafkaApp" \
  --master local[4] \
  target/scala-2.10/simple-project_2.10-1.1.jar

错误：

14/12/30 19:44:57 INFO AkkaUtils: Connecting to HeartbeatReceiver: akka.tcp://sparkDriver@192.168.5.252:65077/user/HeartbeatReceiver
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/spark/streaming/kafka/KafkaUtils$
    at KafkaApp$.main(KafkaApp.scala:28)
    at KafkaApp.main(KafkaApp.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.spark.deploy.SparkSubmit$.launch(SparkSubmit.scala:329)
    at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:75)
    at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.lang.ClassNotFoundException: org.apache.spark.streaming.kafka.KafkaUtils$
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

Answer 1

火花提交不会自动放置包含KafkaUtils的包。你需要在你的项目罐子里。为此，您需要使用sbt assembly创建一个包含所有内容的uber-jar。下面是一个示例build.sbt。

https://github.com/tdas/spark-streaming-external-projects/blob/master/kafka/build.sbt

显然，还需要将程序集插件添加到SBT中。

https://github.com/tdas/spark-streaming-external-projects/tree/master/kafka/project

Answer 2

在提交申请时，请尝试包括所有依赖jars：

提交-名称"SampleApp“-部署模式客户端-主火花://主机:7077-类com.stackexchange.SampleApp --jars com.stackexchange.SampleApp$KAFKA_INSTALL_DIR/libs/zkclient-0.3.jar火花-示例-1.0-SNAPSHOT.jar

Answer 3

跟随build.sbt为我工作。它还要求您将sbt-assembly插件放在projects/目录下的文件中。

build.sbt

name := "NetworkStreaming" // https://github.com/sbt/sbt-assembly/blob/master/Migration.md#upgrading-with-bare-buildsbt

libraryDependencies ++= Seq(
  "org.apache.spark" % "spark-streaming_2.10" % "1.4.1",
  "org.apache.spark" % "spark-streaming-kafka_2.10" % "1.4.1",         // kafka
  "org.apache.hbase" % "hbase" % "0.92.1",
  "org.apache.hadoop" % "hadoop-core" % "1.0.2",
  "org.apache.spark" % "spark-mllib_2.10" % "1.3.0"
)

mergeStrategy in assembly := {
  case m if m.toLowerCase.endsWith("manifest.mf")          => MergeStrategy.discard
  case m if m.toLowerCase.matches("meta-inf.*\\.sf$")      => MergeStrategy.discard
  case "log4j.properties"                                  => MergeStrategy.discard
  case m if m.toLowerCase.startsWith("meta-inf/services/") => MergeStrategy.filterDistinctLines
  case "reference.conf"                                    => MergeStrategy.concat
  case _                                                   => MergeStrategy.first
}

项目/plugins.sbt

addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.1")