It seems the ClassNotFoundException exception is the most common problem. Try point HADOOP_COMMON_HOME to HADOOP_HOME/share/hadoop/common.
In my computer it's /usr/bin/hadoop/share/hadoop/common 在 2011年11月30日 下午6:50，hailong.yang1115 <[email protected]>写道： > Actually I started to play with the latest release 0.23.0 on two nodes > yesterday. And it was easy to start the hdfs. However it took me a while to > configure the yarn. I set the variables HADOOP_COMMON_HOME to where you > extracted the tarball and HADOOP_HDFS_HOME to the local dir where I pointed > the hdfs to. After that I could bring up yarn and run the benchmark. But I > am facing a problem that I could not see the jobs in the UI. And also when > I started the historyserver, I got the following error. > > 11/11/30 20:53:19 FATAL hs.JobHistoryServer: Error starting > JobHistoryServer > java.lang.RuntimeException: java.lang.ClassNotFoundException: > org.apache.hadoop.fs.Hdfs > at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1179) > at > org.apache.hadoop.fs.AbstractFileSystem.createFileSystem(AbstractFileSystem.java:142) > at > org.apache.hadoop.fs.AbstractFileSystem.get(AbstractFileSystem.java:233) > at org.apache.hadoop.fs.FileContext$2.run(FileContext.java:315) > at org.apache.hadoop.fs.FileContext$2.run(FileContext.java:313) > at java.security.AccessController.doPrivileged(Native Method) > at javax.security.auth.Subject.doAs(Subject.java:396) > at > org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1152) > at > org.apache.hadoop.fs.FileContext.getAbstractFileSystem(FileContext.java:313) > at > org.apache.hadoop.fs.FileContext.getFileContext(FileContext.java:426) > at > org.apache.hadoop.fs.FileContext.getFileContext(FileContext.java:448) > at > org.apache.hadoop.mapreduce.v2.hs.JobHistory.init(JobHistory.java:183) > at > org.apache.hadoop.yarn.service.CompositeService.init(CompositeService.java:58) > at > org.apache.hadoop.mapreduce.v2.hs.JobHistoryServer.init(JobHistoryServer.java:62) > at > org.apache.hadoop.mapreduce.v2.hs.JobHistoryServer.main(JobHistoryServer.java:77) > Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.fs.Hdfs > at java.net.URLClassLoader$1.run(URLClassLoader.java:202) > at java.security.AccessController.doPrivileged(Native Method) > at java.net.URLClassLoader.findClass(URLClassLoader.java:190) > at java.lang.ClassLoader.loadClass(ClassLoader.java:306) > at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) > at java.lang.ClassLoader.loadClass(ClassLoader.java:247) > at java.lang.Class.forName0(Native Method) > at java.lang.Class.forName(Class.java:247) > at > org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1125) > at > org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1177) > ... 14 more > Any clue? > > Hailong > > > > > *********************************************** > * Hailong Yang, PhD. Candidate > * Sino-German Joint Software Institute, > * School of Computer Science&Engineering, Beihang University > * Phone: (86-010)82315908 > * Email: [email protected] > * Address: G413, New Main Building in Beihang University, > * No.37 XueYuan Road,HaiDian District, > * Beijing,P.R.China,100191 > *********************************************** > > 发件人： cat fa > 发送时间： 2011-11-30 10:28 > 收件人： common-user > 主题： Re: Re: [help]how to stop HDFS > In fact it's me to say sorry. I used the word "install" which was > misleading. > > In fact I downloaded a tar file and extracted it to ／usr／bin／hadoop > > Could you please tell me where to point those variables？ > > 2011/11/30, Prashant Sharma <[email protected]>: > > I am sorry, I had no idea you have done a rpm install, my suggestion was > > based on the assumption that you have done a tar extract install where > all > > three distribution have to extracted and then export variables. > > Also I have no experience with rpm based installs - so no comments about > > what went wrong in your case. > > > > Basically from the error i can say that it is not able to find the jars > > needed on classpath which is referred by scripts through > > HADOOP_COMMON_HOME. I would say check with the access permission as in > > which user was it installed with and which user is it running with ? > > > > On Tue, Nov 29, 2011 at 10:48 PM, cat fa <[email protected] > >wrote: > > > >> Thank you for your help, but I'm still a little confused. > >> Suppose I installed hadoop in /usr/bin/hadoop/ .Should I > >> point HADOOP_COMMON_HOME to /usr/bin/hadoop ? Where should I > >> point HADOOP_HDFS_HOME? Also to /usr/bin/hadoop/ ? > >> > >> 2011/11/30 Prashant Sharma <[email protected]> > >> > >> > I mean, you have to export the variables > >> > > >> > export HADOOP_CONF_DIR=/path/to/your/configdirectory. > >> > > >> > also export HADOOP_HDFS_HOME ,HADOOP_COMMON_HOME. before your run your > >> > command. I suppose this should fix the problem. > >> > -P > >> > > >> > On Tue, Nov 29, 2011 at 6:23 PM, cat fa <[email protected]> > >> > wrote: > >> > > >> > > it didn't work. It gave me the Usage information. > >> > > > >> > > 2011/11/29 hailong.yang1115 <[email protected]> > >> > > > >> > > > Try $HADOOP_PREFIX_HOME/bin/hdfs namenode stop --config > >> > $HADOOP_CONF_DIR > >> > > > and $HADOOP_PREFIX_HOME/bin/hdfs datanode stop --config > >> > $HADOOP_CONF_DIR. > >> > > > It would stop namenode and datanode separately. > >> > > > The HADOOP_CONF_DIR is the directory where you store your > >> configuration > >> > > > files. > >> > > > Hailong > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > *********************************************** > >> > > > * Hailong Yang, PhD. Candidate > >> > > > * Sino-German Joint Software Institute, > >> > > > * School of Computer Science&Engineering, Beihang University > >> > > > * Phone: (86-010)82315908 > >> > > > * Email: [email protected] > >> > > > * Address: G413, New Main Building in Beihang University, > >> > > > * No.37 XueYuan Road,HaiDian District, > >> > > > * Beijing,P.R.China,100191 > >> > > > *********************************************** > >> > > > > >> > > > From: cat fa > >> > > > Date: 2011-11-29 20:22 > >> > > > To: common-user > >> > > > Subject: Re: [help]how to stop HDFS > >> > > > use $HADOOP_CONF or $HADOOP_CONF_DIR ? I'm using hadoop 0.23. > >> > > > > >> > > > you mean which class? the class of hadoop or of java? > >> > > > > >> > > > 2011/11/29 Prashant Sharma <[email protected]> > >> > > > > >> > > > > Try making $HADOOP_CONF point to right classpath including your > >> > > > > configuration folder. > >> > > > > > >> > > > > > >> > > > > On Tue, Nov 29, 2011 at 3:58 PM, cat fa < > >> [email protected] > >> > > > >> > > > > wrote: > >> > > > > > >> > > > > > I used the command : > >> > > > > > > >> > > > > > $HADOOP_PREFIX_HOME/bin/hdfs start namenode --config > >> > $HADOOP_CONF_DIR > >> > > > > > > >> > > > > > to sart HDFS. > >> > > > > > > >> > > > > > This command is in Hadoop document (here > >> > > > > > < > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > http://hadoop.apache.org/common/docs/r0.23.0/hadoop-yarn/hadoop-yarn-site/ClusterSetup.html > >> > > > > > >) > >> > > > > > > >> > > > > > However, I got errors as > >> > > > > > > >> > > > > > Exception in thread "main" > java.lang.NoClassDefFoundError:start > >> > > > > > > >> > > > > > Could anyone tell me how to start and stop HDFS? > >> > > > > > > >> > > > > > By the way, how to set Gmail so that it doesn't top post my > >> reply? > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > > >
