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https://issues.apache.org/jira/browse/SPARK-1867?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14008329#comment-14008329
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Sean Owen commented on SPARK-1867:
----------------------------------
Well, for example, MapReduce classes are from one of the Hadoop
"hadoop-mapreduce-*" artifacts. Generally speaking, apps depend on "client"
artifacts, which then bring in other necessary dependencies for you. You don't
manually add dependencies for your dependencies; that's what Maven is doing for
you. (Although we all know some artifacts don't express their dependencies 100%
correctly all the time...)
That said, the upstream projects do change over time. For example, in Hadoop
1.x, there was a "hadoop-core" artifact. In Hadoop 2.x things were broken out
further, which is generally good, but now there is "hadoop-common". But you
don't depend on that to use Hadoop, you would use "hadoop-mapreduce-client" for
example if using MapReduce. Same is true of HBase I imagine.
CDH and other distributions do not move things around -- upstream projects do.
Simple use cases are simple to get working. For example if you're using Spark's
core, you just depend on the one spark-core artifact. (With the caveat that you
need to depend on a different Hadoop 2-compatible artifacts if you use Hadoop 2
-- still one artifacts, but may be "0.9.0-cdh5.0.1" for example.) If you use
HBase, you depend on whatever the hbase client artifact is too.
There are gotchas here to be sure, and bits of project-specific knowledge that
are required, but it's not nearly random guesswork. Maybe you can separately
say what you are trying to depend on and people can confirm the few direct
dependencies you should depend on. I suspect there are some fundamental
problems, like depending on the wrong Spark artifact. It sounds like you are
manually trying to replace all of Spark's Hadoop 1 dependencies with Hadoop 2
dependencies, and that way lies madness. Use the one build for Hadoop 2.
> Spark Documentation Error causes java.lang.IllegalStateException: unread
> block data
> -----------------------------------------------------------------------------------
>
> Key: SPARK-1867
> URL: https://issues.apache.org/jira/browse/SPARK-1867
> Project: Spark
> Issue Type: Bug
> Reporter: sam
>
> I've employed two System Administrators on a contract basis (for quite a bit
> of money), and both contractors have independently hit the following
> exception. What we are doing is:
> 1. Installing Spark 0.9.1 according to the documentation on the website,
> along with CDH4 (and another cluster with CDH5) distros of hadoop/hdfs.
> 2. Building a fat jar with a Spark app with sbt then trying to run it on the
> cluster
> I've also included code snippets, and sbt deps at the bottom.
> When I've Googled this, there seems to be two somewhat vague responses:
> a) Mismatching spark versions on nodes/user code
> b) Need to add more jars to the SparkConf
> Now I know that (b) is not the problem having successfully run the same code
> on other clusters while only including one jar (it's a fat jar).
> But I have no idea how to check for (a) - it appears Spark doesn't have any
> version checks or anything - it would be nice if it checked versions and
> threw a "mismatching version exception: you have user code using version X
> and node Y has version Z".
> I would be very grateful for advice on this.
> The exception:
> Exception in thread "main" org.apache.spark.SparkException: Job aborted: Task
> 0.0:1 failed 32 times (most recent failure: Exception failure:
> java.lang.IllegalStateException: unread block data)
> at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$org$apache$spark$scheduler$DAGScheduler$$abortStage$1.apply(DAGScheduler.scala:1020)
> at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$org$apache$spark$scheduler$DAGScheduler$$abortStage$1.apply(DAGScheduler.scala:1018)
> at
> scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
> at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
> at
> org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$abortStage(DAGScheduler.scala:1018)
> at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$processEvent$10.apply(DAGScheduler.scala:604)
> at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$processEvent$10.apply(DAGScheduler.scala:604)
> at scala.Option.foreach(Option.scala:236)
> at
> org.apache.spark.scheduler.DAGScheduler.processEvent(DAGScheduler.scala:604)
> at
> org.apache.spark.scheduler.DAGScheduler$$anonfun$start$1$$anon$2$$anonfun$receive$1.applyOrElse(DAGScheduler.scala:190)
> at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498)
> at akka.actor.ActorCell.invoke(ActorCell.scala:456)
> at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237)
> at akka.dispatch.Mailbox.run(Mailbox.scala:219)
> at
> akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386)
> at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
> at
> scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
> at
> scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
> at
> scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
> 14/05/16 18:05:31 INFO scheduler.TaskSetManager: Loss was due to
> java.lang.IllegalStateException: unread block data [duplicate 59]
> My code snippet:
> val conf = new SparkConf()
> .setMaster(clusterMaster)
> .setAppName(appName)
> .setSparkHome(sparkHome)
> .setJars(SparkContext.jarOfClass(this.getClass))
> println("count = " + new SparkContext(conf).textFile(someHdfsPath).count())
> My SBT dependencies:
> // relevant
> "org.apache.spark" % "spark-core_2.10" % "0.9.1",
> "org.apache.hadoop" % "hadoop-client" % "2.3.0-mr1-cdh5.0.0",
> // standard, probably unrelated
> "com.github.seratch" %% "awscala" % "[0.2,)",
> "org.scalacheck" %% "scalacheck" % "1.10.1" % "test",
> "org.specs2" %% "specs2" % "1.14" % "test",
> "org.scala-lang" % "scala-reflect" % "2.10.3",
> "org.scalaz" %% "scalaz-core" % "7.0.5",
> "net.minidev" % "json-smart" % "1.2"
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