通过zeppelin从docker-hadoop-spark - workbench访问hdfs

Question

我已经安装了https://github.com/big-data-europe/docker-hadoop-spark-workbench

然后用docker-compose up启动它。我导航到the various urls mentioned in the git readme，一切似乎都在上升。

然后我开始了一个本地的apache zeppelin：

./bin/zeppelin.sh start

在zeppelin解释器设置中，我已导航到spark解释器并更新master以指向与docker一起安装的本地群集

大师：从local[*]更新到spark://localhost:8080

然后我在笔记本中运行以下代码：

import  org.apache.hadoop.fs.{FileSystem,Path}

FileSystem.get( sc.hadoopConfiguration ).listStatus( new Path("hdfs:///")).foreach( x => println(x.getPath ))

我在zeppelin日志中遇到此异常：

 INFO [2017-12-15 18:06:35,704] ({pool-2-thread-2} Paragraph.java[jobRun]:362) - run paragraph 20171212-200101_1553252595 using null org.apache.zeppelin.interpreter.LazyOpenInterpreter@32d09a20
 WARN [2017-12-15 18:07:37,717] ({pool-2-thread-2} NotebookServer.java[afterStatusChange]:2064) - Job 20171212-200101_1553252595 is finished, status: ERROR, exception: null, result: %text java.lang.NullPointerException
    at org.apache.zeppelin.spark.Utils.invokeMethod(Utils.java:38)
    at org.apache.zeppelin.spark.Utils.invokeMethod(Utils.java:33)
    at org.apache.zeppelin.spark.SparkInterpreter.createSparkContext_2(SparkInterpreter.java:398)
    at org.apache.zeppelin.spark.SparkInterpreter.createSparkContext(SparkInterpreter.java:387)
    at org.apache.zeppelin.spark.SparkInterpreter.getSparkContext(SparkInterpreter.java:146)
    at org.apache.zeppelin.spark.SparkInterpreter.open(SparkInterpreter.java:843)
    at org.apache.zeppelin.interpreter.LazyOpenInterpreter.open(LazyOpenInterpreter.java:70)
    at org.apache.zeppelin.interpreter.remote.RemoteInterpreterServer$InterpretJob.jobRun(RemoteInterpreterServer.java:491)
    at org.apache.zeppelin.scheduler.Job.run(Job.java:175)
    at org.apache.zeppelin.scheduler.FIFOScheduler$1.run(FIFOScheduler.java:139)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:748)

如何从zeppelin和java / spark代码访问hdfs？

Answer 1

例外的原因是sparkSession对象在Zeppelin中出于某种原因是null。

参考：https://github.com/apache/zeppelin/blob/master/spark/src/main/java/org/apache/zeppelin/spark/SparkInterpreter.java

private SparkContext createSparkContext_2() {
    return (SparkContext) Utils.invokeMethod(sparkSession, "sparkContext");
}

可能是与配置相关的问题。请交叉验证设置/配置和火花群设置。确保火花正常工作。

参考：https://zeppelin.apache.org/docs/latest/interpreter/spark.html

希望这可以帮助。