hadoop - 为什么 ./bin/spark-shell 给出 WARN NativeCodeLoader : Unable to load native-hadoop library for your platform?

Question

在 Mac OS X 上，我使用以下命令从源代码编译了 Spark:

jacek:~/oss/spark
$ SPARK_HADOOP_VERSION=2.4.0 SPARK_YARN=true SPARK_HIVE=true SPARK_GANGLIA_LGPL=true xsbt
...

[info] Set current project to root (in build file:/Users/jacek/oss/spark/)
> ; clean ; assembly
...
[info] Packaging /Users/jacek/oss/spark/examples/target/scala-2.10/spark-examples-1.0.0-SNAPSHOT-hadoop2.4.0.jar ...
[info] Done packaging.
[info] Done packaging.
[success] Total time: 1964 s, completed May 9, 2014 5:07:45 AM

当我启动 ./bin/spark-shell 时，我注意到以下 WARN 消息:

WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

可能是什么问题？

jacek:~/oss/spark
$ ./bin/spark-shell
Spark assembly has been built with Hive, including Datanucleus jars on classpath
14/05/09 21:11:17 INFO SecurityManager: Using Spark's default log4j profile: org/apache/spark/log4j-defaults.properties
14/05/09 21:11:17 INFO SecurityManager: Changing view acls to: jacek
14/05/09 21:11:17 INFO SecurityManager: SecurityManager: authentication disabled; ui acls disabled; users with view permissions: Set(jacek)
14/05/09 21:11:17 INFO HttpServer: Starting HTTP Server
Welcome to
      ____              __
     / __/__  ___ _____/ /__
    _\ \/ _ \/ _ `/ __/  '_/
   /___/ .__/\_,_/_/ /_/\_\   version 1.0.0-SNAPSHOT
      /_/

Using Scala version 2.10.4 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0)
Type in expressions to have them evaluated.
Type :help for more information.
...
14/05/09 21:11:49 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
...

Answer 1

Supported Platforms Apache Hadoop 中的 native 库指南文档如下:

The native hadoop library is supported on *nix platforms only. The library does not to work with Cygwin or the Mac OS X platform.

The native hadoop library is mainly used on the GNU/Linus platform and has been tested on these distributions:

• RHEL4/Fedora
• Ubuntu
• Gentoo

On all the above distributions a 32/64 bit native hadoop library will work with a respective 32/64 bit jvm.

看来在 Mac OS X 上应该忽略 WARN 消息，因为 native 库不仅仅存在于该平台。