我正在一个EC2实例上运行RStudio，该实例具有与之关联的IAM角色，允许对其进行完全S3访问。我想在S3中读入一个文件到RStudio。
我尝试通过sparklyr执行此操作，如下所示：
spark_install(version = "2.1.0")
sc <- spark_connect(master = "local")
ctx <- sparklyr::spark_context(sc)
#Use below to set the java spark context
jsc <- invoke_static(
sc,
"org.apache.spark.api.java.JavaSparkContext",
"fromSparkContext",
ctx
)
hconf <- jsc %>% invoke("hadoopConfiguration")
hconf %>% invoke("set","fs.s3a.impl", "org.apache.hadoop.fs.s3a.S3AFileSystem")
hconf %>% invoke("set","fs.s3.impl", "org.apache.hadoop.fs.s3a.S3AFileSystem")
usercsv_tbl <- spark_read_csv(sc,name = "temp",path = "s3a://<bucket>/filename.csv")
我收到以下错误：
Error: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class org.apache.hadoop.fs.s3a.S3AFileSystem not found
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:2195)
at org.apache.hadoop.fs.FileSystem.getFileSystemClass(FileSystem.java:2654)
at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2667)
at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:94)
at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2703)
at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2685)
at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:373)
at org.apache.hadoop.fs.Path.getFileSystem(Path.java:295)
at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$14.apply(DataSource.scala:372)
at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$14.apply(DataSource.scala:370)
at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:241)
at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:241)
at scala.collection.immutable.List.foreach(List.scala:381)
at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:241)
at scala.collection.immutable.List.flatMap(List.scala:344)
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:370)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:152)
at org.apache.spark.sql.DataFrameReader.csv(DataFrameReader.scala:415)
at org.apache.spark.sql.DataFrameReader.csv(DataFrameReader.scala:352)
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 sparklyr.Invoke$.invoke(invoke.scala:102)
at sparklyr.StreamHandler$.handleMethodCall(stream.scala:97)
at sparklyr.StreamHandler$.read(stream.scala:62)
at sparklyr.BackendHandler.channelRead0(handler.scala:52)
at sparklyr.BackendHandler.channelRead0(handler.scala:14)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:367)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:353)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:346)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:367)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:353)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:346)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:267)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:367)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:353)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:346)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1294)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:367)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:353)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:911)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:131)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:652)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:575)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:489)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:451)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:140)
at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: Class org.apache.hadoop.fs.s3a.S3AFileSystem not found
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:2101)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:2193)
... 52 more
我还尝试使用cloudyr的{{1}}包，如下所示：
aws.s3我收到以下错误：
library(aws.s3)
get_bucket(bucket = <bucketname>)
如何使用EC2的IAM角色访问S3数据，因此我不必手动输入凭据？
答案 0 :(得分：1)
启动Spark时需要包含org.apache.hadoop:hadoop-aws:2.7.3包 - 它允许Spark与S3通信。缺少此程序包是您收到Class org.apache.hadoop.fs.s3a.S3AFileSystem not found错误的原因。
以下适用于我：
config <- spark_config()
config$sparklyr.defaultPackages <- "org.apache.hadoop:hadoop-aws:2.7.3"
Sys.setenv(AWS_ACCESS_KEY_ID="")
Sys.setenv(AWS_SECRET_ACCESS_KEY="") # setting these blank ensures AWS uses the IAM roles associated with the cluster to define S3 permissions
sc <- spark_connect(master='xxxxx', config=config)
有一个很好的指南here