python - 无法在 Jupyter Notebook 中删除或获取或创建 sparkContext

Question

这是我第一次尝试使用 spark 进行机器学习，我打算在 Jupyter Notebook 中使用它。

似乎我遇到了以错误方式实例化火花的问题。显然我只能实例化一个 sparkContext。

我努力了

import findspark
findspark.init()
from pyspark import  SparkContext
sc = SparkContext.getOrCreate()

和

import findspark
findspark.init()
from pyspark import  SparkContext
sc = sc.stop()

这是发布的两个常见解决方案。

如果我不实例化sc，那么sc将是一个身份不明的对象。因此，如果我通过 实例化它.sparkContext()，它会告诉我我不能有多个火花上下文 - 我不确定在笔记本电脑的某个地方可以找到我现有的火花上下文，或者在不知道如何调用这个对象的情况下如何解决这个问题。

我还关闭了我的所有终端（除了让 Jupyter Notebook 保持打开的终端），因为我曾经$pyspark在那里输入过它以检查它是否安装正确。

这是我的错误信息：

Py4JJavaError                             Traceback (most recent call last)
<ipython-input-31-eca205ca2337> in <module>
      2 findspark.init()
      3 from pyspark import  SparkContext
----> 4 sc = SparkContext.getOrCreate()

/usr/local/opt/apache-spark/libexec/python/pyspark/context.py in getOrCreate(cls, conf)
    365         with SparkContext._lock:
    366             if SparkContext._active_spark_context is None:
--> 367                 SparkContext(conf=conf or SparkConf())
    368             return SparkContext._active_spark_context
    369 

/usr/local/opt/apache-spark/libexec/python/pyspark/context.py in __init__(self, master, appName, sparkHome, pyFiles, environment, batchSize, serializer, conf, gateway, jsc, profiler_cls)
    134         try:
    135             self._do_init(master, appName, sparkHome, pyFiles, environment, batchSize, serializer,
--> 136                           conf, jsc, profiler_cls)
    137         except:
    138             # If an error occurs, clean up in order to allow future SparkContext creation:

/usr/local/opt/apache-spark/libexec/python/pyspark/context.py in _do_init(self, master, appName, sparkHome, pyFiles, environment, batchSize, serializer, conf, jsc, profiler_cls)
    196 
    197         # Create the Java SparkContext through Py4J
--> 198         self._jsc = jsc or self._initialize_context(self._conf._jconf)
    199         # Reset the SparkConf to the one actually used by the SparkContext in JVM.
    200         self._conf = SparkConf(_jconf=self._jsc.sc().conf())

/usr/local/opt/apache-spark/libexec/python/pyspark/context.py in _initialize_context(self, jconf)
    304         Initialize SparkContext in function to allow subclass specific initialization
    305         """
--> 306         return self._jvm.JavaSparkContext(jconf)
    307 
    308     @classmethod

/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py in __call__(self, *args)
   1523         answer = self._gateway_client.send_command(command)
   1524         return_value = get_return_value(
-> 1525             answer, self._gateway_client, None, self._fqn)
   1526 
   1527         for temp_arg in temp_args:

/usr/local/opt/apache-spark/libexec/python/pyspark/sql/utils.py in deco(*a, **kw)
     61     def deco(*a, **kw):
     62         try:
---> 63             return f(*a, **kw)
     64         except py4j.protocol.Py4JJavaError as e:
     65             s = e.java_exception.toString()

/usr/local/opt/apache-spark/libexec/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name)
    326                 raise Py4JJavaError(
    327                     "An error occurred while calling {0}{1}{2}.\n".
--> 328                     format(target_id, ".", name), value)
    329             else:
    330                 raise Py4JError(

Py4JJavaError: An error occurred while calling None.org.apache.spark.api.java.JavaSparkContext.
: org.apache.spark.SparkException: Only one SparkContext may be running in this JVM (see SPARK-2243). To ignore this error, set spark.driver.allowMultipleContexts = true. The currently running SparkContext was created at:
org.apache.spark.api.java.JavaSparkContext.<init>(JavaSparkContext.scala:58)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
java.lang.reflect.Constructor.newInstance(Constructor.java:423)
py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:247)
py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
py4j.Gateway.invoke(Gateway.java:238)
py4j.commands.ConstructorCommand.invokeConstructor(ConstructorCommand.java:80)
py4j.commands.ConstructorCommand.execute(ConstructorCommand.java:69)
py4j.GatewayConnection.run(GatewayConnection.java:238)
java.lang.Thread.run(Thread.java:748)
    at org.apache.spark.SparkContext$$anonfun$assertNoOtherContextIsRunning$2.apply(SparkContext.scala:2483)
    at org.apache.spark.SparkContext$$anonfun$assertNoOtherContextIsRunning$2.apply(SparkContext.scala:2479)
    at scala.Option.foreach(Option.scala:257)
    at org.apache.spark.SparkContext$.assertNoOtherContextIsRunning(SparkContext.scala:2479)
    at org.apache.spark.SparkContext$.markPartiallyConstructed(SparkContext.scala:2568)
    at org.apache.spark.SparkContext.<init>(SparkContext.scala:85)
    at org.apache.spark.api.java.JavaSparkContext.<init>(JavaSparkContext.scala:58)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:247)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
    at py4j.Gateway.invoke(Gateway.java:238)
    at py4j.commands.ConstructorCommand.invokeConstructor(ConstructorCommand.java:80)
    at py4j.commands.ConstructorCommand.execute(ConstructorCommand.java:69)
    at py4j.GatewayConnection.run(GatewayConnection.java:238)
    at java.lang.Thread.run(Thread.java:748)

谁能建议我如何解决这个问题，以便我可以实例化一个新的 sparkContext 并继续我的项目？非常感谢！！！

标签： pythonpysparkjupyter-notebook