如何連接Pyspark和Cassandra

Question

所以我正在嘗試將 PySpark 與 Cassandra 連接起來，但我知道如何連接，而且我已經嘗試了很多在 Stack Overflow 和其他頁面中找到的方法。
我收到下一個錯誤py4j.protocol.Py4JJavaError: An error occurred while calling o75.load. .

我用這個命令啟動 pyspark
pyspark --packages com.datastax.spark:spark-cassandra-connector_2.11:2.4.0

我正在使用：

• Python 2.75
• 星火 2.4.0
• Cloudera 6.2.0

Cassandra 有用戶名、密碼和 3 個 ips 即“127.0 0.1,127.0 0.2,127.0 0.1”

我正在使用下一個片段嘗試連接 cassandra：

data_frame = sqlContext.read.format("org.apache.spark.sql.cassandra")\
    .option("spark.cassandra.connection.host",host_casandra)\
    .option("spark.cassandra.auth.username", username_cassandra) \
    .option("spark.cassandra.auth.password", password_cassandra) \
    .options(table=table_casandra, keyspace=keyspace_cassandra).load()

整個錯誤如下：</br>

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
  File "/opt/cloudera/parcels/CDH-6.2.0-1.cdh6.2.0.p0.967373/lib/spark/python/pyspark/sql/readwriter.py", line 172, in load
    return self._df(self._jreader.load())
  File "/opt/cloudera/parcels/CDH-6.2.0-1.cdh6.2.0.p0.967373/lib/spark/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 1257, in __call__
  File "/opt/cloudera/parcels/CDH-6.2.0-1.cdh6.2.0.p0.967373/lib/spark/python/pyspark/sql/utils.py", line 63, in deco
    return f(*a, **kw)
  File "/opt/cloudera/parcels/CDH-6.2.0-1.cdh6.2.0.p0.967373/lib/spark/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o73.load.
: java.lang.NoClassDefFoundError: org/apache/commons/configuration/ConfigurationException
        at org.apache.spark.sql.cassandra.DefaultSource$.<init>(DefaultSource.scala:135)
        at org.apache.spark.sql.cassandra.DefaultSource$.<clinit>(DefaultSource.scala)
        at org.apache.spark.sql.cassandra.DefaultSource.createRelation(DefaultSource.scala:55)
        at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:317)
        at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:223)
        at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:211)
        at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:167)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
        at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
        at py4j.Gateway.invoke(Gateway.java:282)
        at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
        at py4j.commands.CallCommand.execute(CallCommand.java:79)
        at py4j.GatewayConnection.run(GatewayConnection.java:238)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.configuration.ConfigurationException
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 18 more

Answer 1

Cloudera Hadoop 基於 Hadoop 3.0 ，它使用commons-configuration2庫而不是 Spark Cassandra Connector 使用的commons-configuration 。 您可以通過以下方式啟動您的pyspark ：

pyspark --packages com.datastax.spark:spark-cassandra-connector_2.11:2.4.0,commons-configuration:commons-configuration:1.10

顯式添加commons-configuration 。

或者甚至更好，使用spark cassandra 連接器的裝配版本（額外的好處 - 與版本 2.4.0 相比，它具有更多的功能）：

pyspark --packages com.datastax.spark:spark-cassandra-connector-assembly_2.11:2.5.1