It seems u have formatted the namenode twice. In this case the namespace id is not replicated to the datanodes.
Stop all the hadoop daemons and then try the following : 1. vi $PATH_TO_HADOOP_DATASTORE/dfs/name/current/VERSION and copy the namespaceID value. 2.Now open a terminal on every machine having a datanode and do the following: vi $PATH_TO_HADOOP_DATASTORE/dfs/data/current/VERSION Delete the entry corresponding to namespaceID and paste the value copied in Step 1. Save and exit. Restart the hadoop daemons without formatting the namenode. ∞ Shashwat Shriparv On Fri, Nov 16, 2012 at 1:22 PM, shashwat shriparv < dwivedishash...@gmail.com> wrote: > Delete the VERSION for the datanode before format. > > > > ∞ > Shashwat Shriparv > > > > > On Fri, Nov 16, 2012 at 1:15 PM, hadoop hive <hadooph...@gmail.com> wrote: > >> Seems like you havn't format your cluster (if its 1st time made). >> >> On Fri, Nov 16, 2012 at 9:58 AM, a...@hsk.hk <a...@hsk.hk> wrote: >> >>> Hi, >>> >>> Please help! >>> >>> I have installed a Hadoop Cluster with a single master (master1) and >>> have HBase running on the HDFS. Now I am setting up the second master >>> (master2) in order to form HA. When I used JPS to check the cluster, I >>> found : >>> >>> 2782 Jps >>> 2126 NameNode >>> 2720 SecondaryNameNode >>> i.e. The datanode on this server could not be started >>> >>> In the log file, found: >>> 2012-11-16 10:28:44,851 ERROR >>> org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException: >>> Incompatible namespaceIDs in /app/hadoop/tmp/dfs/data: namenode namespaceID >>> = 1356148070; datanode namespaceID = 1151604993 >>> >>> >>> >>> One of the possible solutions to fix this issue is to: stop the >>> cluster, reformat the NameNode, restart the cluster. >>> QUESTION: As I already have HBASE running on the cluster, if I reformat >>> the NameNode, do I need to reinstall the entire HBASE? I don't mind to have >>> all data lost as I don't have many data in HBASE and HDFS, however I don't >>> want to re-install HBASE again. >>> >>> >>> On the other hand, I have tried another solution: stop the DataNode, >>> edit the namespaceID in current/VERSION (i.e. set namespaceID=1151604993), >>> restart the datanode, it doesn't work: >>> Warning: $HADOOP_HOME is deprecated. >>> starting master2, logging to >>> /usr/local/hadoop-1.0.4/libexec/../logs/hadoop-hduser-master2-master2.out >>> Exception in thread "main" java.lang.NoClassDefFoundError: master2 >>> Caused by: java.lang.ClassNotFoundException: master2 >>> 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) >>> Could not find the main class: master2. Program will exit. >>> QUESTION: Any other solutions? >>> >>> >>> >>> Thanks >>> >>> >>> >>> >>> >>> >>> >> >
