Spark3.0 preview预览版尝试GPU调用（本地模式不支持GPU）

　　Spark3.0 preview预览版可以下载使用，地址：https://archive.apache.org/dist/spark/spark-3.0.0-preview/，pom.xml也可以进行引用，如下：

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.spark/spark-core -->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.12</artifactId>
            <version>3.0.0-preview</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.spark/spark-launcher -->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-launcher_2.12</artifactId>
            <version>3.0.0-preview</version>
        </dependency>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_2.12</artifactId>
            <version>3.0.0-preview</version>
        </dependency>
    </dependencies>

注意：目前阿里云镜像部分包还没有（2019年11月10日，spark-launcher_2.12下载没有），可以用国外的。

测试代码：

object SparkPi {
  def main(args: Array[String]): Unit = {
    val spark = SparkSession
      .builder
      .appName("Spark Pi")
      .master("local[2]")
      .config("spark.driver.resource.gpu.discoveryScript", "D:\\gpu.bat")
      .config("spark.worker.resource.gpu.discoveryScript", "D:\\gpu.bat")
      .config("spark.driver.resource.gpu.amount", 1)
      .config("spark.executor.resource.gpu.amount", 1)
      .config("spark.worker.resource.gpu.amount", 1)
      .getOrCreate()
    val slices = if (args.length > 0) args(0).toInt else 2
    val n = math.min(100000L * slices, Int.MaxValue).toInt // avoid overflow
    val count = spark.sparkContext.parallelize(1 until n, slices).map { i =>
      val x = random * 2 - 1
      val y = random * 2 - 1
      if (x * x + y * y <= 1) 1 else 0
    }.reduce(_ + _)
    println(s"Pi is roughly ${4.0 * count / (n - 1)}")
 
    spark.stop()
  }
}

其中，gpu.bat的内容如下：

@echo off
echo {"name": "gpu", "addresses": [""]}

运行日志如下：

2019-11-10 00:39:33,429 [main] INFO  [org.apache.spark.SparkContext] - Running Spark version 3.0.0-preview
2019-11-10 00:39:34,915 [main] INFO  [org.apache.spark.resource.ResourceUtils] - ==============================================================
2019-11-10 00:39:34,918 [main] INFO  [org.apache.spark.resource.ResourceUtils] - Resources for spark.driver:
gpu -> [name: gpu, addresses: 0]
2019-11-10 00:39:34,919 [main] INFO  [org.apache.spark.resource.ResourceUtils] - ==============================================================
20

我以为可以成功调用GPU，查看任务管理器里面的GPU显示，并没有发现，最后搜索代码，在"spark-3.0.0-preview\core\src\main\scala\org\apache\spark\scheduler\local\LocalSchedulerBackend.scala"(85,56)显示如下：

  def reviveOffers(): Unit = {
    // local mode doesn't support extra resources like GPUs right now
    val offers = IndexedSeq(new WorkerOffer(localExecutorId, localExecutorHostname, freeCores,
      Some(rpcEnv.address.hostPort)))
    for (task <- scheduler.resourceOffers(offers).flatten) {
      freeCores -= scheduler.CPUS_PER_TASK
      executor.launchTask(executorBackend, task)
    }
  }

注释：local mode doesn't support extra resources like GPUs right now

本地模式不支持GPU

心一凉，本来打算搭建standalone模式，最后看了一下window的搞不了，Linux的得个虚拟机了，比较笨资源有限，就暂不试了。