更改hadoop native库文件后datanode故障
hadoop是用cloudra的官方yum源安装的,服务器是CentOS6.3 64位操作系统,自己写的mapreduce执行的时候hadoop会提示以下错误:
WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
网上说是这样的
Hadoop的native是在32 bit环境下编译的,在64bit环境下运行会有问题,所以需要下载hadoop的源码在64bit环境下重新编译
然后在官方文档里找到了相应的解释
链接:http://hadoop.apache.org/docs/r2.5.1/hadoop-project-dist/hadoop-common/NativeLibraries.html
The pre-built 32-bit i386-Linux native hadoop library is available as part of the hadoop distribution and is located in the lib/native directory. You can download the hadoop distribution from Hadoop Common Releases. Be sure to install the zlib and/or gzip development packages - whichever compression codecs you want to use with your deployment.
于是,按照官档里的说明在服务器上Build出新的hadoop,把native里面的库文件替换默认的的库文件,搞定,重启hadoop所有服务,自己写的mapreduce可以用了,那么接下来问题来了……发现hdfs进入了Safemode,说有个多少多少块corrupted,然后发现重启期间有同事在使用mapreduce,怀疑是这个原因造成了数据的损坏。由于数据有备份,于是手动解除Safemode,用hadoo fsck删掉了坏掉的数据块,此时是不提示corrupted了,可是惊奇的发现,datanode没有起来!
Hadoop datanode is dead and pid file exists
紧接着,找到存在的pid file,rm之,再起!还是不行!找到datanode的日志,发现有FATAL信息!
2014-11-26 14:35:49,577 FATAL org.apache.hadoop.hdfs.server.datanode.DataNode: Exception in secureMain
java.lang.UnsatisfiedLinkError: org.apache.hadoop.io.nativeio.SharedFileDescriptorFactory.createDescriptor0(Ljava/lang/String;Ljava/lang/St
ring;I)Ljava/io/FileDescriptor;
at org.apache.hadoop.io.nativeio.SharedFileDescriptorFactory.createDescriptor0(Native Method)
at org.apache.hadoop.io.nativeio.SharedFileDescriptorFactory.create(SharedFileDescriptorFactory.java:87)
at org.apache.hadoop.hdfs.server.datanode.ShortCircuitRegistry.<init>(ShortCircuitRegistry.java:169)
at org.apache.hadoop.hdfs.server.datanode.DataNode.initDataXceiver(DataNode.java:586)
at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:773)
at org.apache.hadoop.hdfs.server.datanode.DataNode.<init>(DataNode.java:292)
at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:1893)
at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:1780)
at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:1827)
at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:2003)
at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:2027)
2014-11-26 14:35:49,580 INFO org.apache.hadoop.util.ExitUtil: Exiting with status 1
2014-11-26 14:35:49,582 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down DataNode at carweb94/10.14.1.94